1. C++ Program
A sequence of structured statements written by programmer using C++ language to solve a problem.
Using Visual C++ to write your program
1- Start  Programs  Microsoft Visual Studio 6  Microsoft Visual C++ 6
2- File  New  Files  C++ Source file  oK
3- Write your program using C++ statements
4- Compilation: Ctrl + F7 to see if the program has error's
5- Execution: to display the program’s result
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2. General form of C++ Program
#include <iostream.h> void main() { C++ statements }
Remark: C++ language is case sensitive
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3. Problem : Compute and print the summation of two numbers.
Program
#include <iostream.h> void main() { int a, b, s; cout<<"Please Enter two numbers:"; cin>>a>>b; s = a + b; cout<<"s="<<s<<endl; }

4. Remarks: - iostream.h: C++ library that contains all input/output statements and other constrols. - main(): the main function of the program which represents the program’s life time. - a, b, and s are three variables of type integer. Their values can be any integer and can be changed. - cin>>: C++ statement to take value(s) from the user. - cout<<: C++ statements to display value(s) to the output screen. - " ": must be around any character constants. - \n or endl: to start new line at output screen.
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5. Variables Variables: - Variable is one memory location.
-The name of the location is the variable name.
-The location content is the value of the variable
- You can change the content of the variable at any
time in the statements of the algorithm.
e.g.
Name of the location Inside Memory location
employee_name "Ali Ahmed"
age
hourly_rate
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6. Data Types Variable declaration
Predefined Data Types:
int : values (e.g , , 12)
operations (e.g. + , - , * , / , % , >, <, = =, !=, > =, <= )
float (double) : values (e.g , 1.23E+5 , 0.34E-2)
operations (e.g. +, -, *, /, , >, <, = =, !=, > =, <= )
bool : values (true , false)
operations (e.g. AND, OR, NOT)
char : values (e.g. ‘A’ , ‘t’ , ‘(‘ , ‘5’ , ‘;’ )
operations (e.g. <, > , ≤, etc.)
Variable declaration
Type Variable_name
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7. Constant Values: can be numerical (3, 100, -5, 3
Constant Values: can be numerical (3, 100, -5, 3.14) or string (‘A’, ‘$’, ‘Ahmad’, Amman).
Constant identifier: one memory location take a value at a first time, which can not be changed.
const float pi = 3.14
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8. Variable names int X,x,Number, IF,If,iF,a7,Total_sum; float _abc;
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9. Problem : Compute and print the average of three numbers.
Program
#include <iostream.h> void main() { int n1, n2, n3; float s, average; cout<<"Please Enter three integers: "; cin>>n1>>n2>>n3; s = n1 + n2 + n3; average = s / 3; cout<<"Average = \t"<<average<<endl; }
Remark: \t to leave tab spaces
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10. Problem : Compute the area of the circle. Where area = π x R2
Program
#include <iostream.h> void main() { const double Pi = 3.14; int r; cout<<"Please enter r : "; cin>>r; double a; a = Pi * r * r; cout<<"Circle's Area = "<<a<<endl; }
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11. Examples on integer division
#include <iostream.h>
void main( ) {
int x;
x=1/3*3; // /3=0
cout<<x<<endl;
x=1.0/3*3; }
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12. Boolean variables and relational operations
#include <iostream.h>
void main( ) {
bool x,y;
x= 5 > 7;
cout<<x<<endl;
y= 5 < 7;
cout<<y<<endl;
x=true;
y=false;
x=5;
cout<<x; }
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13. Misleading examples X= 7 > 5 > 3;
This expression gives false because its evaluated as follows
X=(7>5) >3;
= > 3; // False;
The relational operations are executed from left to right
< ,<= ,> , >= have the same priority
== , != have lower priority than the above.
X = 1 == 1>3;
X = 3>4 == 4>3;
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14. Priority * , / , % have the same priority ( High )
+ , - have the same priority (Low)
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15. Examples on arithmetic operations
The order of execution is as follows:
* , then + , then -
X= * 3 – 7 / 3
Execution order : * , + , / , -
X= 5+2*3/4%1-7/3
……………………..
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16. If Statement in C++ One way if if ( Condition ) statement;
if ( Condition ) { statements; }
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17. Problem : Read any number from the user, then print positive if it is positive.
Program
#include <iostream.h> void main() { int Num; cout<<"Please Enter an integer number:"; cin>>Num; if (Num > 0) cout<<" Positive\n"; }
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18. Another Version
#include <iostream.h> void main() { int Num; bool w;
cout<<"Please Enter an integer number:"; cin>>Num;
w=Num>0; if (w) cout<<" Positive\n"; }
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19. If Statement in C++ Two way if
if ( Condition ) statement; else statement;
if ( Condition ) { statements; } else { statements;}
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20. Write a program that reads a mark, if mark is 60 or greater, the program prints PASS, else it will print FAIL
#include <iostream.h> void main() { int mark; cout<<"Please Enter your mark: "; cin>>mark; if (mark>=60) cout<<" PASS\n";
else
cout<<"FAIL\n"; }
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21. More than one statement in the if
#include <iostream.h> void main() { int mark; cout<<"Please Enter your mark: "; cin>>mark; if (mark>=60) {
cout<<" PASS\n";
cout<<" you can take Object course now\n"; }
else {
cout<<"FAIL ";
cout<<"You must take this course again\n";
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22. Write a program that prints the fraction a/b in the form c d/b Example: 7/3 = 2 1/3
#include <iostream.h>
void main ( ) {
int a,b,c,d;
cout<<"To convert the fraction from the format a/b to c d/b, Enter a,b";
cin>>a>>b;
c=a/b;
d=a%b;
cout<<a<<"/"<<b<<"="<<c<<" "<<d<<"/"<<b<<endl; }
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23. Enhancement on the previous example
#include <iostream.h>
void main ( ) {
int a,b,c,d;
cout<<"To convert the fraction from the format a/b to c d/b, Enter a,b";
cin>>a>>b;
c=a/b;
d=a%b;
cout<<a<<"/"<<b<<"=";
if ( c != 0)
cout<<c;
if (d!=0)
cout<<" "<<d<<"/"<<b;
cout<<endl; }
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24. Arithmetic Expressions
Condition
Condition: An expression that is evaluated to produce only true or false values.
Arithmetic Expressions
- It is composed of operands and arithmetic
operations ( + , - , *, /, %).
- Its result is a numeric value
(e.g gives 7)
- Operands may be numbers and/or identifiers that have numeric values.
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25. Relational Expressions
- It is composed from operands and operators.
- Operands may be numbers and/or identifiers
that have numeric values
- Its result is a logical value (true or false).
- Operators are relational operators:
< , > , <= , >= , = =, !=
e.g.
(a < b) gives true, if value of a is less than value of b
false, if value of a is not less than value of b
(x != y) also gives true or false according to the values of x
and y
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26. Logical Expressions - It is called also Boolean expression.
- It is composed from operands and operators.
- Operands are identifiers that have logical values
- Its result is a logical value (true or false) (see later).
- Operators are logical: &&(AND) , ||(OR), !(NOT)
e.g.
X && Y
a && b || c
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27. Evaluating Logical Expressions
The truth table
AND table
&& True False
True True False
False False False
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28. (2) OR table || True False True True True False True False
(3) NOT table
! True False
False True
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29. Arithmetic  Relational  Logical
NOTES
A relational expression may contain arithmetic sub expressions,
e.g. ( ) < (12 * 4 )
< 12 * 4
2) A logical expression may contain relational and arithmetic subexpressions,
e.g.
x && y && ( a > b )
(2 + t ) < (6 * w ) && ( p = =q )
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30. Operator Precedence Precedence Description Operator Highest
parentheses
( )
unary plus, unary minus, Not
+, – , !
*, /, %
Binary plus, binary minus
+ , -
<, <=, >, >=
Equal, not equal
== , !=
&& ||
Lowest
Assignment =
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31. Examples Find the value of the following expression: (1) 5 + 8 * 2 / 4
(1) * / 4 16 4
(This is the final result)
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32. Find the value of the following expression
( ) / 12 2
10`
(this is the final result)
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33. Find the value of the following Expression
If x = True, y = False, z = False, find the value of the expression x && y || z
x && y || z
False
False (the final result)
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34. Another example X=true, Y=false, Z= true X || Y && Z true
X=true, Y=false, Z= false
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35. Find the value of the following Expression
If a = 3, b = 5, x = true, y = false, find the value of the expression: ( a < b ) AND y OR x
( a < b ) && y || x
True
False
True (the final result)
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36. What is the output of the following code:
Program
#include <iostream.h> void main() { int a=10, b=3; cout<<"\n a+b= \t"<<a+b; cout<<"\n a+b*2= \t"<<a+b*2; cout<<"\n (a+b)*2 \t"<<(a+b)*2<<endl; cout<<a<<"<"<<b<<" is\t"<<(a<b); cout<<"\n a+b != a+3 is \t"<<(a+b != a+3); cout<<"\n a+b >= b*2 || a>b+9 is \t"<<(a+b >= b*2 || a>b+9); cout<<endl; }
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37. Problem : Read any number from the user, then print positive if it is positive and print negative otherwise.
Program
#include <iostream.h> void main() { int Num; cout<<"Please Enter Number:"; cin>>Num; if (Num < 0) cout<<"Negative\n"; else cout<<"Positive\n"; }
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38. Problem : Read Two numbers from the user, then print the greatest one.
Program
#include <iostream.h> void main() { int x,y; cout<<"Please Enter two numbers:"; cin>>x>>y; cout<<"Max = "; if (x > y) cout<<x<<endl; else cout<<y<<endl; }
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39. Problem : Read three numbers to print the smallest one.
Program
#include <iostream.h> void main() { int a, b, c; cout<<"Please Enter three numbers:"; cin>>a>>b>>c; cout<<"Min= "; if ((a < b) && (a < c)) cout<<a; if ((b < a) && (b < c)) cout<<b; if ((c < a) && (c < b)) cout<<c; cout<<endl; }
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40. Program2 (Nested if)
#include <iostream.h> void main() { int a, b, c; cout<<"\nPlease Enter three numbers:"; cin>>a>>b>>c; cout<<"\nMin= "; if (a < b) if (a < c) cout<<a; else cout<<c; else if (b < c) cout<<b; else cout<<c; cout<<endl; }
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41. Problem : Read number, if it is positive, Add number 10 to it and print the Number "is positive", but otherwise, subtract number 10 from it and print the Number "is negative".
Program
#include <iostream.h> void main() { int Number; cout<<"Please enter Number:"; cin>>Number; if (Number>0) { Number = Number + 10; cout<<Number<<" is Positive\n";} else { Number = Number - 10; cout<<Number<<" is Negative\n";} }
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42. Example on dangling else
if ( x>y)
if ( x<z)
cout<<" Hello";
else
cout<<"Hi";
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43. Another idea if ( x>y) {if ( x<z) cout<<" Hello";} else
cout<<"Hi";
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44. Assignment Statement Simple Assignment: Max = 5 ; Max = A ; F = A+B*2;
Compound Assignment: A += 10 ;  A = A + 10; A -= C ;  A = A – C; I *= 4 ;  I = I * 4; r /= 2;  r = r / 2; S %= 3 ;  S = S % 3 ; B &= true;  B = B && true; B |= true;  B = B || true;
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45. Increment and Decrement
Postfix C++;  use the value of C, then increment (C = C+1) it. C--;  use the value of C, then decrement (C = C-1) it.
Prefix ++C; increment the value of C (C = C+1), then use it . --C; Decrement the value of C (C = C-1), then use it .
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46. What is the output of the following C++ Source Code
Program
#include <iostream.h> void main( ) { int A=10, B=4, R; cout<<"A="<<A<<"\tB="<<B; A += B; B *= 2; cout<<"\nA="<<A<<"\tB="<<B; R = ++A % B--; cout<<"\nR="<<R; R = A B ; cout<<"\nA="<<A<<"\tB="<<B<<"\tR="<<R; bool a=true, b=false; a &= b; if (a == 0) cout<<"\n a = false\n"; else cout<<"\n a = true\n"; }
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47. Examples X=5; Y=7; X++; cout<<X<<endl; ++X;
Z=X++ + Y; // Z=X+Y; X=X+1;
cout<<X<<" "<<Y<<" "<<Z<<endl;
Z=++X +Y; // X=X+1; Z=X+Y;
Z=X++ + Y++; // Z=X+Y; X++;Y++;
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48. Loop (iteration statements) used to repeat subcode number of times there three loop techniques: 1- for Loop. 2- while Loop. 3- do … while Loop
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49. For Loop Technique
General Form: for (counter_var=initial_val; condition; increasing or decreasing counter_var) { . Statement(s); . }
Statements will be executed repeatedly while condition is true. When the condition become false, the loop will be terminated and the execution sequence will go the first statement after for loop. If the loop body contains only one statement, there is no need to begin{ and end } the loop body.
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50. Problem : Print the word "Amman" five times.
Program
#include <iostream.h> void main( ) { for (int i=1; i<=5; i++) cout<<"Amman\n"; }
Another Program
#include <iostream.h> void main() { for (int i=5; i>=1; i--) cout<<"Amman\n"; }
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51. Problem : Print the following numbers. 1 3 5 7 9 11
Program
#include <iostream.h> void main( ) { for (int k=1; k<=11; k+=2) cout<<k<<"\t"; cout<<endl; }
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52. Problem : Print the following numbers. 20 17 14 11 8 5 2
Program
#include <iostream.h> void main() { for (int m=20; m>=2; m-=3) cout<<m<<"\t"; cout<<endl; }
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53. Another Version of the previous example
#include <iostream.h> void main( ) {
int m; for (m=20; m>=2; m-=3) cout<<m<<"\t"; cout<<endl; }
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54. Another Version of the previous example
#include <iostream.h> void main( ) {
int m=20; for ( ; m>=2; m-=3) cout<<m<<"\t"; cout<<endl; }
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55. Quiz
Write a program that prints the numbers from X to Y, with step Z , using for statement. The program should read X, Y, Z then start the loop
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56. Problem : Print the following numbers. 1 2 3 4 … n(entered by user)
Program
#include <iostream.h> void main() { int n; cout<<"\nPlease enter the upper limit:"; cin>>n; for (int i=1; i<=n; i++) cout<<i<<"\t"; cout<<endl; }
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57. Problem : Print the following numbers
Problem : Print the following numbers. L (entered By user) (L+1) (L+2) … U (entered By user)
Program
#include <iostream.h> void main() { int L,U; cout<<"Enter the start value:"; cin>>L; cout<<"Enter the end value:"; cin>>U; for (int i=L; i<=U; i++) cout<<i<<"\t"; cout<<endl; }
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58. Problem : Read five numbers from the user and print the positive numbers only.
Program
#include <iostream.h> void main() { int num; for (int i=1; i<=5; i++) { cout<<"Please Enter No "<<i<<':'; cin>>num; if (num > 0) cout<<num<<" is positive\n"; } }
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59. Problem : Read five numbers from the user and print the positive numbers only.
#include <iostream.h> void main() { int num; for (int i=1; i<=5; i++) { cout<<"Please Enter No "<<i<<':'; cin>>num; if (num < 0) continue; cout<<num<<" is positive\n"; } }
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60. Problem : Compute and print S, Where S = 1+ 2+ 3+ 4+ 5
#include <iostream.h> void main() { int S=0; for (int i=1; i<=5; i++) S+=i; cout<<"Sum is "<<S<<endl; }
Program
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61. Problem : Compute and print S, Where Sum = 1+ 3+ 5+ 7+ … + n
Program
#include <iostream.h> void main( ) { int Sum=0, n; cout<<"Please Enter n"; cin>>n; for (int i=1; i<=n; i+=2) Sum+=i; cout<<"Sum="<<Sum<<endl; }
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62. Problem : print the following formula Sum = 1+ 3+ 5+ 7+ … + n
Program
#include <iostream.h> void main( ) { int n; cout<<"Please Enter n"; cin>>n; cout<<"Sum= "; for (int i=1; i<=n; i+=2) cout<<i<<"+"; cout<<"\b \n"; }
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63. Problem : Compute and print the summation of any 10 numbers entered by the user.
Program
#include <iostream.h> void main() { int S=0, N; for (int i=10; i>=1; i--) { cout<<"Please Enter the next number:"; cin>>N; S+=N;} cout<<"S="<<S<<endl; }
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64. Problem : Compute and Print the factorial of the number 5. (Fact = 5 * 4 * 3 * 2 * 1)
Program
#include <iostream.h> void main( ) { int Fact=1; for (int j=5; j>=1; j--) Fact *= j; cout<<"5! = "<<Fact<<endl; }
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65. A program to find n!
#include <iostream.h> void main( ) { int Fact=1,n; cout<<"Enter an integer to find its factorial";
cin>>n;
for (int j=n; j>=1; j--) Fact *= j; cout<<n<<"!= "<<Fact<<endl; } Try it on n = 17 ???
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66. Problem : Compute and Print the value of M where M = 2 * 4 * 6 * … * n
Program
#include <iostream.h> void main( ) { long M=1; int n; cout<<"please enter the upper Limit:"; cin>>n; for (int i=2; i<=n; i+=2) M *= i; cout<<"M= "<<M<<endl; }
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67. Problem : Compute and Print Mn
Program
#include <iostream.h> void main() { long Result=1; int M, n; cout<<“Enter the Base number:"; cin>>M; cout<<“Enter the exponent:"; cin>>n; for (int i=1; i<=n; i++) Result *= M; cout<<"Result= "<<Result<<endl; }
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68. Write a program that finds Mn for positive & negative n
H.W.
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69. General Form: while (Condition) { . Statement(s); . }
While Technique
General Form: while (Condition) { . Statement(s); . }
Statements will be executed repeatedly while condition is true. When the condition become false, the loop will be terminated and the execution sequence will go to the first statement after While loop. If the loop body contains only one statement, there is no need to begin{ and end } the loop body.
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70. Problem : Print the word "Amman" five times.
Program
#include <iostream.h>
void main() {
int i=1;
while (i<=5) {
cout<<"Amman\n";
i++; }
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71. #include <iostream.h> void main() { int i=1; while (i++<=5) {
cout<<"Amman\n"; }
cout<<i<<endl;
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72. Problem : Print the following numbers. 1 3 5 7 9 11
Program
#include <iostream.h>
void main() {
int i=1;
while (i <= 11) {
cout<<i<<'\t';
i+=2; } }
Remark:
Write ((i+=2) <= 11 ) condition instead of the above one. What changes you have to do to produce the same output.
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73. Problem : Print the following numbers. 20 17 14 … n
Program
#include <iostream.h>
void main() {
int n, k=20;
cout<<"Enter the lower limit:";
cin>>n;
while ( k >= n) {
cout<<k<<'\t';
k -= 3; }
cout<<endl; }
Remark:
Write k-=3 instead of k in the above condition. What you have to do to produce the same output.
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74. Problem : Read five numbers from the user and print the positive numbers only.
Program
#include <iostream.h>
void main() {
int num, j=0;
while ( j++ < 5 ) {
cout<<"Enter the next num:";
cin>>num;
if (num > 0)
cout<<num<<endl; } }
Remark:
Solve the above problem by using continue statement.
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75. #include <iostream.h> void main() { int sum=0,i,x,y;
cout<<"Enter x,y please: ";
cin>>x>>y;
i=x;
while ( i <=y) {
sum=sum+i;
i=i+1; }
cout<<"The Sum for the numbers from "<<x<<" to " <<y<<" = "<<sum<<endl;
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76. Problem : Compute and print S, Where Sum = 1+ 3+ 5+ 7+ … + n
Program
#include <iostream.h>
void main() {
int n, Sum=0, i=1;
cout<<"Enter the upper limit:";
cin>>n;
while ( i <= n ) {
Sum += i;
i += 2; }
cout<<"\nSum="<<Sum; }
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77. Problem : Read 10 numbers by the user and compute and print the summation of numbers, which are divisible by 3.
Program
#include <iostream.h>
void main() {
int Num, Sum=0, i=1;
while ( i <= 10 ) {
cout<<"Enter a number:";
cin>>Num;
if (Num % 3 == 0)
Sum += Num;
i++; }
cout<<"\nSum="<<Sum;
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78. Problem : Compute and Print the value of M where M = 2 * 4 * 6 * … * n
Program
#include <iostream.h>
void main() {
int N, M=1, i=2;
cout<<"Enter the upper limit:";
cin>>N;
while ( i <= N ) {
M *= i;
i += 2; }
cout<<"\nM="<<M; }
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79. #include <iostream.h> void main() { int N, M=1, i=2;
cout<<"Enter the upper limit:";
cin>>N;
cout<<"\nM=1";
while ( i <= N ) {
M *= i;
cout<<" x "<<i;
i += 2; }
cout<<"="<<M<<endl; }
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80. General Form: do { . Statement(s); . } while (Condition) ;
Do .. While Technique
General Form: do { . Statement(s); . } while (Condition) ;
Statements will be executed repeatedly while condition is true. When the condition become false, the loop will be terminated and the execution sequence will go to the first statement after the loop. The loop body will be executed at least one.
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81. Problem : Print the word "Amman" five times.
Program
#include <iostream.h>
void main( ) {
int i = 1;
do {
cout<<"Amman\n";
i++;
} while (i <= 5); }
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82. Execute the following program
#include <iostream.h>
void main() {
int Choice, Num;
do {
cout<<"\n Enter the New Number";
cin>>Num;
if (Num % 2 == 0)
cout<<Num<<" is Even\n";
else
cout<<Num<<" is Odd\n";
cout<<"Select your choice.\n";
cout<<"1- Exit. (Terminate the Run)\n";
cout<<"2- Enter New Number to Check.\n";
cin>>Choice;
} while (Choice != 1); }
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83. #include <iostream.h> void main() { int Num; char Choice; do {
cout<<"\n Enter the New Number";
cin>>Num;
if (Num % 2 == 0)
cout<<Num<<" is Even\n";
else
cout<<Num<<" is Odd\n";
cout<<"Enter Y to continue, any other character to exit \n";
cin>>Choice;
} while (Choice == ‘Y’); }
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84. #include <iostream.h> void main() { int Num; char Choice; do {
cout<<"\n Enter the New Number";
cin>>Num;
if (Num % 2 == 0)
cout<<Num<<" is Even\n";
else
cout<<Num<<" is Odd\n";
cout<<"Enter Y to continue, any other character to exit \n";
cin>>Choice;
} while ((Choice == 'Y') || (Choice=='y')); }
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85. Homework
Resolve all problems in the presentation 5 and 6 by using the three loop techniques: For, While, and Do … while Loops.
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86. 2.10 break and continue Statements
break statement
Immediate exit from while, for, do/while, switch
Program continues with first statement after structure
Common uses
Escape early from a loop
Skip the remainder of switch
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87. 2 // Using the break statement in a for structure.
// Fig. 2.26: fig02_26.cpp
// Using the break statement in a for structure.
#include <iostream> 4
using std::cout;
using std::endl; 7
// function main begins program execution
int main()
10 { 11
int x; // x declared here so it can be used after the loop 13
// loop 10 times
for ( x = 1; x <= 10; x++ ) { 16
// if x is 5, terminate loop
if ( x == 5 )
break; // break loop only if x is 5 20
cout << x << " "; // display value of x 22
} // end for
Exits for structure when break executed.
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88. 27 return 0; // indicate successful termination 28 24
25 cout<< "\nBroke out of loop when x became "<< x <<endl; 26
return 0; // indicate successful termination 28
29 } // end function main
Broke out of loop when x became 5
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89. 2.10 break and continue Statements
Used in while, for, do/while
Skips remainder of loop body
Proceeds with next iteration of loop
while and do/while structure
Loop-continuation test evaluated immediately after the continue statement
for structure
Increment expression executed
Next, loop-continuation test evaluated
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90. 2 // Using the continue statement in a for structure.
// Fig. 2.27: fig02_27.cpp
// Using the continue statement in a for structure.
#include <iostream> 4
using std::cout;
using std::endl; 7
// function main begins program execution
int main()
10 {
// loop 10 times
for ( int x = 1; x <= 10; x++ ) { 13
// if x is 5, continue with next iteration of loop
if ( x == 5 )
continue; // skip remaining code in loop body 17
cout << x << " "; // display value of x 19
} // end for structure
Skips to next iteration of the loop.
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91. Used continue to skip printing the value 521
22 cout<< "\nUsed continue to skip printing the value 5"
<< endl; 24
return 0; // indicate successful termination 26
27 } // end function main
Used continue to skip printing the value 5
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92. 2.8 switch Multiple-Selection Structure
Test variable for multiple values
Series of case labels and optional default case
switch ( variable ) { case value1: // taken if variable == value1
statements
break; // necessary to exit switch
case value2:
case value3: // taken if variable == value2 or == value3
break;
default: // taken if variable matches no other cases
statements break; }
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93. 2.8 switch Multiple-Selection Structure93
2.8 switch Multiple-Selection Structure
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94. Example on switch statement
#include<iostream.h>
void main()
{ int a;
cout<<“ Enter an Integer between 0 and 10: “;
cin>>a;
switch(a)
{ case 0:
case 1: cout<<“hello ”;
case 2: cout<<“there ”;
case 3: cout<<“Welcome to ”;
case 4: cout<<“C++ ”<<endl;
break;
case 5: cout<<“How “;
case 6:
case 7:
case 8: cout<<“are you “<<endl;
case 9: break;
case 10: cout<<“Have a nice day. “<<endl;
default: cout<<“Sorry, the number is out of range.”<<endl; }
cout<< “ out of switch structure.”<<endl; } //main
Example on switch statement 94
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95. Another switch example
void main( ) {
int score;
char grade;
cin>>score;
switch(score/10) {
case 0: case 1: case 2:
case 3: case 4: case 5: grade = ‘F’;
break;
case 6: grade = ‘D’;
case 7: grade = ‘C’;
case 8: grade = ‘B’;
case 9: case 10: grade = ‘A’;
default: cout<<“Invalid test score.”<<endl; }
cout<<“Grade is”<<grade<<endl;
} // end main 95
Another switch example
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96. switch examples void main( ) { char grade;96
switch examples
void main( ) {
char grade;
cout <<“ Enter grade as a letter : ” ;
cin>>grade;
switch(grade)
{case ‘A’: cout<<“The Grade is A”;
break;
case ‘B’: cout<<“The Grade is B”;
case ‘C’: cout<<“The Grade is C”;
case ‘D’: cout<<“The Grade is D”;
case ‘F’: cout<<“The Grade is F”;
default: cout<< “The Grade is invalid”; }
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97. switch examples void main( ) { int age;97
switch examples
void main( ) {
int age;
cout<<“Enter your age: “;
cin>>age;
switch (age>=18)
case 1: cout<<“old enough to take a driving license.”<<endl;
cout<< “old enough to vote.”<<endl;
break;
case 0: cout<<“Not old enough to take a driving license”<<endl;
cout<< “Not old enough to vote.”<<endl; }
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98. cout<<"Enter ur mark "; cin>>score; char grade;
void main()
{ int score;
cout<<"Enter ur mark ";
cin>>score;
char grade;
switch(score/10)
{ case 0: case 1: case 2: case 3: case 4: case 5:
grade = 'F'; break;
case 6: grade = 'D';
break;
case 7: grade = 'C';
case 8: grade = 'B';
case 9: case 10: grade = 'A';
default: cout<<"Invalid test score."<<endl; } //End of switch
cout<<"Your grade is "<<grade<<endl; }
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99. Nested for Print the following shape ***** cin>>n;
for(int i=1;i<=n;i++)
{ for (int j=1;j<=n;j++)
cout<<"*";
cout<<endl; }
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100. Problem : Draw the following shape * ** *** **** *****
Nested for
Problem : Draw the following shape * ** *** **** *****
#include <iostream.h> void main( ) { for (int raw=1; raw<=5; raw++) { for (int C=1; C<=raw; C++) cout<<'*'; cout<<endl; } }
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101. Problem : Draw the following shape ***** **** *** ** *
#include <iostream.h> void main() { for (int i=1; i<=5; i++) { for (int j=i; j<=5; j++) cout<<'*'; cout<<endl; } }
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102. What is the output for the following program
for(int i=1;i<=5;i++) {
for (int j=1;j<=5;j++)
if (i==j) cout<<"*";
else
if (i+j==6)
cout<<"*";
cout<<" ";
Cout<<endl;}
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103. Problem : display the multiplication table for the number 3.
#include <iostream.h>
void main() {
for (int i=1; i<=10; i++)
cout<<"3 x "<<i<<" = "<<3*i<<endl; }
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104. Problem : display the multiplication table for the numbers from 1 to 5.
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105. for (int i=1;i<=5;i++) { for(int j=1;j<=5;j++)
cout<<i*j<<"\t";
cout<<endl; }
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106. Problem : Read any number from the user and print Prime if it is a prime number, or Not prime otherwise.
#include <iostream.h>
void main() {
bool Prime = true;
int i, num;
cout<<"Please enter the number:";
cin>>num;
for ( i=2; i<num; i++)
if (num%i==0) {
Prime = false;
break; }
if (Prime)
cout<<num<<" is a Prime number\n";
else
cout<<num<<" is not a Prime number\n"; }
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107. S=m0 + m1 + … +mn #include <iostream.h> void main()
{int s=0,n,m;
int t=1;
cout<<"Enter m please ";
cin>>m;
cout<<"Enter n please ";
cin>>n;
for (int i=0;i<=n;i++)
{ t=1;
for (int j=1;j<=i;j++)
t=t*m;
s=s+t; }
cout<<s<<endl;
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108. #include <iostream.h> void main() {int s=0,n,m; int t=1;
cout<<"Enter m please ";
cin>>m;
cout<<"Enter n please ";
cin>>n;
for (int i=0;i<=n;i++) {
s=s+t;
t=t*m; }
cout<<s<<endl;
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109. Nested Loops #include <iostream.h> 1 2 3 4 void main() {
int i,j=1;
while(j<=4){
i=1;
while(i<=4){
cout<<i<<"\t";
i++; }
j++;
cout<<endl;
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110. Problem : Draw the following shape * ** *** **** *****
#include <iostream.h>
void main() {
int i=1;
while (i<=5) {
int j=1;
while (j<=i) {
cout<<'*';
j++;}
cout<<endl;
i++; } }
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111. for (int i=1;i<=4;i++) {int x=1; for(int j=1;j<=i;j++)
1 2
1 2 4
for (int i=1;i<=4;i++)
{int x=1;
for(int j=1;j<=i;j++)
{cout<<x<<" ";
x=x*2;}
cout<<endl;}
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112. for (int i=1;i<=4;i++) {for(int j=0;j<i;j++) {int x=1;
for( int k=1;k<=j;k++)
x=2*x;
cout<<x<<" ";}
cout<<endl;}
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113. Functions
Chapter 3
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114. Topics to be covered C++ pre defined functions: User Functions:
Math library functions
Random function
Examples on rand with switch statments
User Functions:
Function proto type
Function definition:
Square, Cube examples
Examples on the four forms of functions, And their meaning ( when to use each form):
void F(void)
void F(int)
int F(void)
int F(int)
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115. Call by value & call By reference Functions on arrays
Scope of variables &Global variables
Recursion :
Factorial
Febonacci,
Sum of numbers from x to y
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116. Math library functions:
ceil(x),floor(x)
fabs(x), fmod(x,y), pow(x,y),sqrt(x)
sin(x), cos(x), tan(x)
These functions are of type double, and take also double arguments
They belong to the library
#include <cmath>
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117. Examples double Y; Y=pow( 5,4); Y=pow(5,-4); Y=pow(5.2,3);
Y=pow(-4,0.5); runtime error
Y=pow(x*3/7,y-1);
Y=pow(floor(x/3),ceil(x/4));
Y=sqrt(9);
Y=sqrt(10);
Y=sqrt(0.09);
Y=sqrt(-16); runtime error
cout<<ceil(5.2);
ceil(0.1);
ceil(-0.1);
ceil(-1.1);
floor(5.2);
floor(0.1);
floor(-0.1);
floor(-1.1);
ceil(5.2/3);
floor(ceil(5.2/3));
fabs( );
fmod(5,3) ≡ 5%3
fmod(4.2,2);
fmod(5.1,2.5)
fmod(7.7,2.5)
Examples
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118. #include <iostream.h> #include <cmath> void main() {
double A,B,C,X,Y;
cout<<"Enter a number :";
cin>>X;
Y=X/180* ;
A=sin(Y);
B=cos(Y);
C=tan(Y);
cout<<"sin("<<X<<") = "<<A<<endl;
cout<<"cos("<<X<<") = "<<B<<endl;
cout<<"tan("<<X<<") = "<<C<<endl; }
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119. Problem : Read any number from the user and print it is prime if it is, or not prime otherwise.
#include <iostream.h>
#include <cmath>
void main() {
bool Prime = true;
int i, num;
cout<<"Please enter the number:";
cin>>num;
for ( i=2; i<=sqrt(num); i++)
if (num%i==0) {
Prime = false;
break; }
if (Prime)
cout<<num<<" is a Prime number\n";
else
cout<<num<<" is not a Prime number\n"; }
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120. Random number generator
#include <cstdlib>
X=rand(); // gives a random number // between
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121. #include <iostream.h> #include <cstdlib> void main() {
int x;
for( int i=1;i<=100;i++)
{x=rand();
cout<<x<<endl;} }
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122. Generate 20 random numbers between 0 - 9
#include <iostream.h>
#include <cstdlib>
void main() {
int x;
for( int i=1;i<=20;i++)
{x=rand()%10;
cout<<x<<endl;} }
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123. 20 numbers between 1 - 10 #include <iostream.h>
#include <cstdlib>
void main() {
int x;
for( int i=1;i<=20;i++)
{x=rand()%10+1;
cout<<x<<endl;} }
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124. Generate 10 integer random numbers between 5 - 7
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125. Using srand function #include <cstdlib> void main() {
int x,seed;
cout<<"Enter the seed for the random generater ";
cin>>seed;
srand(seed);
for( int i=1;i<=10;i++)
x=rand();
cout<<x<<endl;} }
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126. Q: Write a program that generates 1200 random numbers between 1-6, and also counts the occurrence of each number? Its expected that the occurrence of each number will be about 200 times. But remember we are talking about random number. No exact values.
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127. #include <iostream.h> #include <cstdlib> void main()
{ int x,count1=0, count2=0, count3=0, count4=0, count5=0, count6=0;
for( int i=1;i<=1200;i++) {
x=rand()%6 +1;
if (x==1) count1++;
if (x==2) count2++;
if (x==3) count3++;
if (x==4) count4++;
if (x==5) count5++;
if (x==6) count6++;
cout<<x<<endl;}
cout<<1<<" : "<<count1<<endl;
cout<<2<<" : "<<count2<<endl;
cout<<3<<" : "<<count3<<endl;
cout<<4<<" : "<<count4<<endl;
cout<<5<<" : "<<count5<<endl;
cout<<6<<" : "<<count6<<endl; }
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128. A program to count the occurrence of each random number
#include <iostream.h>
#include <cstdlib>
void main()
{ int x,count[7]={0};
for( int i=1;i<=1200;i++) {
x=rand()%6 +1;
if (x==1) count[1]++;
if (x==2) count[2]++;
if (x==3) count[3]++;
if (x==4) count[4]++;
if (x==5) count[5]++;
if (x==6) count[6]++;
cout<<x<<endl;}
for(i=1;i<=6;i++)
cout<<i<<" : "<<count[i]<<endl; }
A program to count the occurrence of each random number
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129. The same example using Switch statement
#include <iostream.h>
#include <cstdlib>
void main()
{ int x,count[7]={0};
for( int i=1;i<=1200;i++) {
x=rand()%6 +1;
switch(x)
case 1: count[1]++;
break;
case 2: count[2]++;
case 3: count[3]++;
case 4: count[4]++;
case 5: count[5]++;
case 6: count[6]++; }
for(i=1;i<=6;i++)
cout<<i<<" : "<<count[i]<<endl;
The same example using Switch statement
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130. Do the same prev. example,
Count the number of even numbers, and the number of odd numbers.
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131. #include <iostream.h> #include <cstdlib> void main()
{ int x,even=0,odd=0;
for( int i=1;i<=1200;i++) {
x=rand()%6 +1;
switch(x)
case 1:
case 3:
case 5: odd++;
break;
case 2:
case 4:
case 6: even++; }
cout<<"Even count is "<<even<<endl;
cout<<"Odd count is "<<odd<<endl;
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132. #include <iostream.h> #include <cstdlib> void main() {
int x,count[7]={0};
for( int i=1;i<=1200;i++)
x=rand()%6 +1;
count[x]++;
cout<<x<<endl;}
for(i=1;i<=6;i++)
cout<<i<<" : "<<count[i]<<endl; }
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133. User Defined Functions
Write a function that calculates and returns the square value of a double number:
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134. #include <iostream.h>
double square(double); // function prototype
void main( )
{double x,y;
cout<<"Enter a number :";
cin>>x;
y=square(x);
cout<<x<<" squared = "<<y<<endl; }
double square(double a)
{ double b;
b=a*a;
return b;
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135. Another user defined function
Write a program to calculate and print a rectangle area, the program should use a function to calculate and returns the area of a rectangle to the main program?
This function should take the length and the width , and should return the area
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136. #include <iostream.h>
double area(double,double); // function prototype
void main( ){
double L,W,A;
cout<<"Enter the length:";
cin>>L;
cout<<"Enter the width:";
cin>>W;
A=area(L,W);
cout<<"The area of the recangle is "<<A; }
double area(double X,double Y)
{ double Z;
Z=X*Y;
return Z;
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137. Write a program that finds and prints the maximum of three integer numbers, The program should use a function to find the maximum value.
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138. #include <iostream.h> int max(int,int,int); void main(){
int x,y,z;
cout<<"Enter 3 numbers please :";
cin>>x>>y>>z;
cout<<"The Maximum is "<<max(x,y,z)<<endl; }
int max(int a,int b,int c)
{int m;
m=a;
if (m<b) m=b;
if (m<c) m=c;
return m;}
وائل قصاص

139. #include <iostream.h> #include <cmath> bool prime(int);
void main(){
int x;
cout<<"Enter a number please :";
cin>>x;
if (prime(x))
cout<<x<<" is a prime number\n";
else
cout<<x<<" is not a prime number\n"; }
bool prime(int a)
{bool p=true;
for(int i=2;i<=sqrt(a);i++)
if (a%i==0)
{ p=false;
break;}
return p;}
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140. Build your own fabs function
#include <iostream.h>
double fabs(double);
void main(void) {
double x,y;
cout<<"Enter a number ";
cin>>x;
y=fabs(x);
cout<<"The absolute value of "<<x<<" is "<<y<<endl; }
double fabs(double m)
if (m>=0)
return m;
else
return -m;
وائل قصاص

141. Forms of functions Functions that take inputs and returns output:
double square(double), int max(int a, int b, int c) ….
Functions that take inputs but don’t return output
void Printsum(int x,int y)
Functions that don’t take any inputs but returns an output:
int Read_number(void);
Functions that don’t take and inputs and don’t return any input
void Print_hello(void);
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142. Write a program that uses a function to calculate and print the sum of two numbers.
#include <iostream.h>
void print_sum(int,int);
void main()
{int x,y;
cout<<"Enter two numbers please :";
cin>>x>>y;
print_sum(x,y); }
void print_sum(int x,int y)
{int s;
s=x+y;
cout<<x<<"+"<<y<<" = "<<s<<endl;
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143. Write a program that reads two numbers and prints the sum of them, This program should use a function to read the numbers and use another function to calculate and print the sum of two numbers
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144. #include <iostream.h> void print_sum(int,int);
int read_number(void);
void main()
{int x,y;
x=read_number();
y=read_number();
print_sum(x,y); }
void print_sum(int x,int y)
{int s;
s=x+y;
cout<<x<<"+"<<y<<" = "<<s<<endl;
int read_number(void)
{int A;
cout<<"Enter a number please ";
cin>>A;
return A;
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145. Write a progam that uses a function to print a welcome message
#include <iostream.h>
void print_welcome(void);
void main(){
print_welcome(); }
void print_welcome(void) {
cout<<"Hello, Welcome in C++ functions\n";
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146. Modify the previous example, make the main calls the print function 10 times
Also, make the print_welcome function print a random message from 3 different messages
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147. #include <iostream.h> #include<cstdlib>
void print_welcome(void);
void main(){
for(int i=1;i<=10;i++)
print_welcome(); }
void print_welcome(void)
{int x=rand()%3;
switch(x)
{case 0: cout<<"Hello \n"; break;
case 1: cout<<"Welcome \n";break;
case 2: cout<<"Hi, how are u \n";
وائل قصاص

148. Inputs for any function
The inputs for a function could be:
constants: x=sqrt( 9);
Variables x=sqrt(y);
Expression x=sqrt(y+3*z);
Or even another function x=sqrt(ceil(y/3));
This is valid for library functions , and user defined functions also
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149. Scope of variables with functions
#include <iostream.h>
int x=10; // global variables
int f1(int);
void f2(int);
int f3(void); // int f3();
void main(void)
{cout<<x<<endl;
int x=15;
cout<<x<<endl;
cout<<::x<<endl;
for (int i=1;i<3;i++) {
int x=5;
int y=x+::x;
cout<<y<<" "<<x<<" "<<::x<<endl; }
cout<<f1(x)<<endl;
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150. cout<<x<<endl; int x=13; f2(x);
int f1(int a) {
cout<<x<<endl;
int x=13;
f2(x);
cout<<::x<<endl;
return x+a; }
void f2(int b)
{cout<<x<<endl;
x=x-b;
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151. Aliasing #include<iostream.h> int main() { int x; int &y=x; x=5;
int &z=y;
cout<<x<<"\t"<<y<<"\t"<<z<<endl;
y=7;
y=x+z-3;
return 0; }
وائل قصاص

152. Call By value & call By reference
#include <iostream.h>
int square(int);
void main() {
int x,y;
cout<<"Enter a number ";
cin>>x;
y=square(x);
cout<<x<<" squared is "<<y<<endl; }
int square(int a) // call by value
a=a*a;
return a; }
وائل قصاص

153. #include <iostream.h> void square(int &); void main() { int x;
cout<<"Enter a number ";
cin>>x;
cout<<x<<" squared is ";
square(x);
cout<<x<<endl; }
void square(int & a) // call by reference
a=a*a;
وائل قصاص

154. #include<iostream.h> void read_two_numbers(int &,int &);
void main()
{int x,y;
read_two_numbers (x,y);
cout<<x<<" "<<y<<endl; }
void read_two_numbers (int & a,int &b) {
cout<<"Enter two numbers please "
cin>>a>>b;
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155. Static variables and default arguments
#include <iostream.h>
void f(int x=10 );
void main() {
f();
f(5);
f(7); }
void f(int x)
{static int abc=17;
abc++;
cout<<abc<<"\t"<<x<<endl;
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156. Recursive functions Factorial Febonacci series Sum between X, Y
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157. Recursive fact #include <iostream.h> int fact(int); void main(){
int x;
cout<<"Enter a number to calculate its factorial ";
cin>>x;
cout<<x<<"! = "<<fact(x)<<endl; }
int fact(int n)
if (n==1)
return 1;
else
return n*fact(n-1);
Recursive fact
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158. Recursive fact #include <iostream.h> int fact(int); void main(){
int x;
cout<<"Enter a number to calculate its factorial ";
cin>>x;
cout<<x<<"! = "<<fact(x)<<endl; }
int fact(int n)
if (n==1)
{cout<<"Now returning fact 1\n";
return 1;
else
{cout<<"Now calling fact "<<n-1<<endl;
return n*fact(n-1);
Recursive fact
وائل قصاص

159. #include <iostream.h> int fact(int); void main() { int x;
cout<<"Enter a number to calculate its factorial ";
cin>>x;
cout<<x<<"! = "<<fact(x)<<endl; }
int fact(int n)
if (n==1)
{cout<<"Now returning fact 1\n";
return 1;
else
{cout<<"Now calling fact "<<n-1<<endl;
int m= n*fact(n-1);
cout<<"Returning "<<n<<"!="<<m<<endl;
return m;
وائل قصاص

160. Feb(n)=feb(n-1)+feb(n-2)
وائل قصاص

161. #include <iostream.h> int feb(int); void main() { int x;
cout<<"Enter a number to calculate its febonacci ";
cin>>x;
cout<<"Feb("<<x<<") = "<<feb(x)<<endl; }
int feb(int n)
if (n==0)
return 0;
else
if (n==1)
return 1;
return feb(n-1)+feb(n-2);
وائل قصاص

162. #include <iostream.h> int feb(int); void main() { int x;
cout<<"Enter a number to calculate its febonacci ";
cin>>x;
cout<<feb(x)<<endl; }
int feb(int n){
if (n==0) return 0;
else
if (n==1) return 1;
return feb(n-1)+feb(n-2);
وائل قصاص

163. Febonacci using for #include <iostream.h> int feb(int);
void main() {
int x;
cout<<"Enter a number to calculate its febonacci ";
cin>>x;
cout<<feb(x)<<endl; }
int feb(int n){
int fn_2=0;
int fn_1=1;
int fn;
for(int i=2;i<=n;i++)
{fn=fn_2+fn_1;
fn_2=fn_1;
fn_1=fn;
return fn;
Febonacci using for
وائل قصاص

164. Sum of numbers from 1 to n #include <iostream.h> int sum(int);
void main() {
int x;
cout<<"Enter a number to calculate the sum ";
cin>>x;
cout<<"Sum of the series "<<sum(x)<<endl; }
int sum(int n)
if (n==1)
return 1;
else
return n+sum(n-1);
وائل قصاص

165. Write a function that returns the sum of numbers from X to Y
Write a function that returns the sum of numbers from X to Y. The function should calculate the sum recursively
∑ i = y+ ∑ i y
y-1
i=x
i=x
وائل قصاص

166. Sum of numbers from X to Y
#include <iostream.h>
int sum(int,int);
void main() {
int x,y;
cout<<"Enter two numbers to calculate the sum ";
cin>>x>>y;
cout<<"Sum of the series "<<sum(x,y)<<endl; }
int sum (int a, int b)
if (a==b)
return b;
else
return b+sum(a,b-1);
وائل قصاص

167. Array One Dimensional array Two Dimensional array
Array is a set of adjacent memory locations of the same data type. All of them have one name, which is the array name. each location has subscript number started by zero.
One Dimensional array
Data_Type array_name[How many elements] ;
Two Dimensional array
Data_Type array_name[#Rows][#Columns] ;
وائل قصاص

168. One Dimensional array int List[5];
List[0] List[1] list[2] list[3] list[4]
Print Elements for(i=0; i<5; i++) cout<<List[i];
Read Elements List[0] = 100; List[1] = 30; List[2] = 10; List[3] = -20; List[4] = 5;
وائل قصاص

169. Definitions and initial values
int X[4]={4,2,3,1};
int A[10]={0};
int B[100]={1};
int C[7]={1,2,6};
int d[5];
int E[ ]={4,6,2};
وائل قصاص

170. Not accepted Statements
int A[4]={4,2,4,5,2};
int E[ ];
int n=5;
int X[n];
Corrected by:
const int n=5;
وائل قصاص

171. #include <iostream.h> void main() {
int A[5] = {10,20,15,100,30};
for (int i=0; i<5; i++)
cout<<A[i]<<'\t';
for (i=0; i<5; i++) {
cout<<"\nPlease Enter A["<<i<<"]:";
cin>>A[i]; }
for (i=0; i<5; i++)
cout<<endl; }
وائل قصاص

172. #include <iostream.h> void main() {
int A[5] = {10,20,15,100,30};
for (int i=0; i<5; i++)
cout<<A[i]<<'\t';
for (i=0; i<5; i++) {
cout<<"\nPlease Enter A["<<i<<"]:";
cin>>A[i]; }
for (i=0; i<5; i++)
cout<<endl; }
وائل قصاص

173. #include <iostream.h> void main() {
const int Size = 10;
char KeyBSym[Size]={ ')', '!', '#', '$', '%', '^', '&', '*', '(' };
for (int i=0; i<Size; i++)
cout<<"Shift + number "<<i<<" Give Symbol "<<KeyBSym[i]<<endl; }
وائل قصاص

174. #include <iostream.h> const int S = 10; void main() { int A[S];
for(int i=0; i<S; i++) {
cout<<"\nEnter A["<<i<<"]:";
cin>>A[i]; }
int PositiveSum = 0, EvenSum = 0,
Gthan10_Count = 0;
for (i=0; i<S; i++) {
if (A[i]>0)
PositiveSum += A[i];
if (A[i]%2 == 0)
EvenSum += A[i];
if (A[i]>10)
Gthan10_Count++; }
cout<<"\nSummation of positive Elements: "<<PositiveSum;
cout<<"\nSummation of Even Elements: "<<EvenSum;
cout<<"\n# Element, which are greater than 10: "<<Gthan10_Count;
cout<<endl;
وائل قصاص

175. #include <iostream.h> const int S = 10; void main() { int A[S];
for(int i=0; i<S; i++) {
cout<<"\nEnter A["<<i<<"]:";
cin>>A[i]; }
long Even_Position_Mul = 1, Odd_Position_Mul = 1;
for (i=0; i<S; i++)
if(i%2==0)
Even_Position_Mul *= A[i];
else
Odd_Position_Mul *=A[i];
cout<<"\nMultiplication of elements at Even position: "<<Even_Position_Mul;
cout<<"\nMultiplication of elements at Odd position: "<<Odd_Position_Mul;
cout<<endl; }
وائل قصاص

176. Find the Maximum element
#include <iostream.h>
const int Size = 10;
void main() {
int Vector[Size];
for(int i=0; i<Size; i++)
cin>>Vector[i];
for(i=0; i<Size; i++)
cout<<Vector[i]<<'\t';
cout<<endl;
int Max = Vector[0];
for(i=1; i<Size; i++)
if (Max<Vector[i])
Max=Vector[i];
cout<<"\nMax= "<<Max<<endl; }
وائل قصاص

177. Search #include <iostream.h> const int Size = 10; void main() {
int Vector[Size];
for(int i=0; i<Size; i++)
cin>>Vector[i];
cout<<endl;
int Element;
cout<<"What is the element that you looking for";
cin>>Element;
bool Found = false;
for(i=0; i<Size; i++)
if(Element = = Vector[i]){
Found = true;
break; }
if (Found)
cout<<Element<<" Found at position "<<i<<endl;
else
cout<<Element<<" is not in the array \n";}
وائل قصاص

178. Another version of search example
#include <iostream.h>
const int Size = 10;
void main() {
int Vector[Size];
for(int i=0; i<Size; i++)
cin>>Vector[i];
cout<<endl;
int Element;
cout<<"What is the element that you are looking for: ";
cin>>Element;
bool Found = false;
for(i=0; i<Size; i++)
if(Element == Vector[i]){
cout<<Element<<" is found at position "<<i<<endl;
Found=true; }
if (!Found)
cout<<Element<<" is not in the array \n"; }
وائل قصاص

179. Sort the elements: #include <iostream.h> const int Size = 5;
void main() {
int Vector[Size];
for(int i=0; i<Size; i++)
cin>>Vector[i];
for(i=0; i<Size; i++)
cout<<Vector[i]<<'\t';
cout<<endl;
for(i=0; i<Size - 1; i++)
for(int j=i+1; j<Size; j++)
if (Vector[i]>Vector[j]) {
int Temp = Vector[i];
Vector[i] = Vector[j];
Vector[j] = Temp;}
cout<<endl; }
وائل قصاص

180. build a swap function function
void swap(int & x,int & y) {
int temp;
temp=x;
x=y;
y=temp; }
وائل قصاص

181. Bubble sort using the swap function
#include <iostream.h>
void swap(int &,int &);
const int Size = 5;
void main() {
int Vector[Size];
for(int i=0; i<Size; i++)
cin>>Vector[i];
for(i=0; i<Size - 1; i++)
for(int j=i+1; j<Size; j++)
if (Vector[i]>Vector[j]) swap(Vector[i],Vector[j]);
for(i=0; i<Size; i++)
cout<<Vector[i]<<'\t';
cout<<endl; }
void swap(int & x,int & y) {
int temp;
temp=x;
x=y;
y=temp; }
Bubble sort using the swap function
وائل قصاص

182. Arrays and Call by reference
We can’t return the array using return statement.
We need to use the call by reference technique.
BUT when passing an array to a function, it is sent as call by reference.
No need to declare it as int &[ ]
وائل قصاص

183. Write a function that return the sum of an array
#include <iostream.h>
int Arr_Sum(int [ ],int);
void main( ) {
int A[5]={2,3,4,5,6};
int B[4]={5,3,1,7};
cout<<"The sum of A is "<<Arr_Sum(A,5)<<endl;
cout<<"The sum of B is "<<Arr_Sum(B,4)<<endl; }
int Arr_Sum(int x[ ],int size)
{int S=0;
for(int i=0;i<size;i++)
S=S+x[ i ];
return S;
وائل قصاص

184. Functions to Read and print arrays
#include <iostream.h>
void Arr_read(int [ ],int);
void Arr_print(int[ ],int);
void main(){
int A[5];
int B[4];
Arr_read(A,5);
Arr_read(B,4);
Arr_print(A,5);
Arr_print(B,4);}
void Arr_read(int x[ ],int size)
{ for(int i=0;i<size;i++)
{cout<<"Enter a number please ";
cin>>x[i];} }
void Arr_print(int x[ ],int size)
{for(int i=0;i<size;i++)
cout<<x[i]<<" ";
cout<<endl;
Functions to Read and print arrays
وائل قصاص

185. Function to calculate the sum of two arrays
#include <iostream.h>
void sum(int [ ],int [ ],int[ ],int);
void main() {
int a[4]={4,3,2,1};
int b[4]={2,2,4,4};
int c[4];
sum(a,b,c,4);
Arr_print(c,4); }
void sum(int x[ ],int y[ ],int z[ ],int s)
for (int i=0;i<s;i++)
z[i]=x[i]+y[i];
وائل قصاص

186. cout statement with setw( )
#include <iostream.h>
#include <iomanip.h>
void main() {
for(int i=1; i<= 5;i++) // without using setw( )
cout<<i<<" "<<i*i<<" "<<i*i*i<<endl;
cout<<endl;
for(i=1; i<= 5;i++) // with using setw( )
cout<<setw(4)<<i<<setw(4)<<i*i<<setw(4)<<i*i*i<<endl; }
وائل قصاص

187. Strings #include <iostream.h> void main() { char n[10];
char a[10]={'A','h','m','e','d'};
for(int i=0; a[i]!=0 ; i++)
cout<<a[i]<<endl;
cout<<endl; }
وائل قصاص

188. Q1 in the exam #include <iostream.h> void main() { int a[4][3];
for(int i=0;i<4;i++)
for(int j=0;j<3;j++)
{ cout<<"Enter a number ";
cin>>a[i][j]; }
for(int k=0;k<3;k++)
int s=0;
for(int m=0;m<4;m++)
s=s+a[m][k];
cout<<s<<endl;
وائل قصاص

189. Two Dimensional array int Matrix[3][4]; 30 1 2
Assign values to Elements Matrix[0][1] = 30; Matrix[1][0] = 100; Matrix[1][2] = 10; Matrix[2][3] = -20; Matrix[2][0]=Matrix[1][2];
Print Elements for(i=0; i<3; i++){ for(j=0; j<4; j++) cout<<Matrix[i][j]<<"\t"; cout<<endl; }
وائل قصاص

190. int A[2][3] = { {1 ,2 , 3 }, {10,20,30}}; int Matrix[3][4]= {{0,30 },
{100,0,10},
{0,0,0,-20}};
وائل قصاص

191. #include <iostream.h> void main() {
int A[2][3] = {{1,2,3},{10,20,30}};
int B[2][3] = {100,200,300,40,50,60};
int C[2][3] = {{15,25},{105,205}};
for( int i=0; i<2; i++){
for( int j=0; j<3; j++)
cout<<A[i][j]<<'\t';
cout<<endl; }
cout<<endl;
for( i=0; i<2; i++){
cout<<B[i][j]<<'\t';
cout<<C[i][j]<<'\t'; }
وائل قصاص

192. #include <iostream.h> const int Rows = 3, Columns = 4;
void main() {
int A[Rows][Columns];
for (int i=0; i<Rows; i++)
for (int j=0; j<Columns; j++) {
cout<<"\nEnter A["<<i<<"]["<<j<<"]:";
cin>>A[i][j]; }
for (i=0; i<Rows; i++){
for(int j=0; j<Columns; j++)
cout<<A[i][j]<<'\t';
cout<<endl; } }
وائل قصاص

193. Find The sum of 2-D arrays using functions`
#include <iostream.h>
int A_sum(int [ ][2],int);
void main(){
int x[3][2]={6,5,4,3,2,1};
int y[4][2]={5,4,3,2,3,4,1};
cout<<"The sum of the array x is " <<A_sum(x,3)<<endl;
cout<<"The sum of the array y is " <<A_sum(y,4)<<endl; }
int A_sum(int a[ ][2],int r) {
int s=0;
for(int i=0;i<r;i++)
for(int j=0;j<2;j++)
s=s+a[i][j];
return s;
Find The sum of 2-D arrays using functions`
وائل قصاص

194. Diagonal Summation #include <iostream.h>
const int Rows = 4, Columns = 4;
void main() {
int A[Rows][Columns];
for (int i=0; i<Rows; i++)
for (int j=0; j<Columns; j++) {
cout<<"\nEnter A["<<i<<"]["<<j<<"]:";
cin>>A[i][j]; }
int DSum = 0;
for (i=0; i<Rows; i++)
DSum += A[i][i];
cout<<"Diagonal Sum = "<<DSum<<endl; }
وائل قصاص

195. Inverse Diagonal Summation
#include <iostream.h>
const int Rows = 4, Columns = 4;
void main() {
int A[Rows][Columns];
for (int i=0; i<Rows; i++)
for (int j=0; j<Columns; j++) {
cout<<"\nEnter A["<<i<<"]["<<j<<"]:";
cin>>A[i][j]; }
int DSum = 0;
for (i=0; i<Rows; i++)
for (int j=0; j<Columns; j++)
if ( i+j= = 3)
DSum += A[i][j];
cout<<"Diagonal Sum = "<<DSum<<endl; }
وائل قصاص

196. Lower Triangular Multiplication
#include <iostream.h>
const int Rows = 4, Columns = 4;
void main() {
int A[Rows][Columns];
for (int i=0; i<Rows; i++)
for (int j=0; j<Columns; j++) {
cout<<"\nEnter A["<<i<<"]["<<j<<"]:";
cin>>A[i][j]; }
long LTmul = 1;
for (i=1; i<Rows; i++)
for(int j=0; j<i; j++)
LTmul *= A[i][j];
cout<<"Lower Traingular Mul = "<<LTmul<<endl; }
وائل قصاص

197. Lower Triangular Multiplication
#include <iostream.h>
const int Rows = 4, Columns = 4;
void main() {
int A[Rows][Columns];
for (int i=0; i<Rows; i++)
for (int j=0; j<Columns; j++) {
cout<<"\nEnter A["<<i<<"]["<<j<<"]:";
cin>>A[i][j]; }
long LTmul = 1;
for (i=0; i<Rows; i++)
for(int j=0; j<Columns,; j++)
if (i>j) LTmul *= A[i][j];
cout<<"Lower Traingular Mul = "<<LTmul<<endl; }
وائل قصاص

198. Write a Program that copies an array to another
#include <iostream.h>
const int R = 4, C= 3;
void main() {
int A[R][C];
int B[R][C];
for (int i=0; i<R; i++)
for (int j=0; j<C; j++) {
cout<<"\nEnter A["<<i<<"]["<<j<<"]:";
cin>>A[i][j]; }
for (i=0 ;i<R;i++)
for(int j=0;i<C;j++)
B[i][j]=A[i][j];
for (i=0; i<R; i++){
for(int j=0; j<C; j++)
cout<<B[i][j]<<'\t';
cout<<endl; } }
وائل قصاص

199. Write a function that copies a 2-D array to another
void copyA(int x[ ][3],int y[ ][3],int r) {
for(int i=0;i<r;i++)
for(int j=0;j<3;j++)
y[i][j]=x[i][j]; }
وائل قصاص

200. Write a Program that copies an array to another
#include <iostream.h>
const int R = 4, C= 3;
void main() {
int A[R][C];
int B[R][C];
for (int i=0; i<R; i++)
for (int j=0; j<C; j++) {
cout<<"\nEnter A["<<i<<"]["<<j<<"]:";
cin>>A[i][j]; }
copyA(A,B,4);
for (i=0; i<R; i++){
for(int j=0; j<C; j++)
cout<<B[i][j]<<'\t';
cout<<endl; } }
وائل قصاص

201. Store the following symbols in the array Symbol.
* $ $ $
# * $ $
# # * $
#include <iostream.h>
const int Rows = 4, Columns = 4;
void main() {
char Symbol[Rows][Columns];
for (int i=0; i<Rows; i++)
for (int j=0; j<Columns; j++)
if (i == j)
Symbol[i][j] = '*';
else if (i > j)
Symbol[i][j] = '#';
else
Symbol[i][j] = '$';
for (i=0; i<Rows; i++){
for(int j=0; j<Columns; j++)
cout<<Symbol[i][j];
cout<<endl; } }
# # # *
وائل قصاص

202. Matrix Matrix Summation
#include <iostream.h>
const int Rows = 4, Columns = 4;
void main() {
int A[Rows][Columns], B[Rows][Columns], C[Rows][Columns];
cout<<"\nEnter Matrix A elements:\n";
for (int i=0; i<Rows; i++)
for( int j=0; j<Columns; j++)
cin>>A[i][j];
cout<<"\nEnter Matrix B elements:\n";
for (i=0; i<Rows; i++)
cin>>B[i][j];
for(i=0; i<Rows; i++)
for(int j=0; j< Columns; j++)
C[i][j] = A[i][j] + B[i][j];
for(i=0; i<Rows; i++){
for(int j=0; j<Columns; j++)
cout<<C[i][j]<<'\t';
cout<<endl; } }
وائل قصاص

203. Write a function to add two Arrays
void add(int x[ ][4],int y[ ][4],int z[ ][4],int r) { }
وائل قصاص

204. Compute the average for 5 marks for 10 students
int marks [10][5];
for(int i=0;i<10;i++)
for(int j=0;j<5;j++)
{ cout<<"Enter mark"<<j+1<<" for student"<<i+1;
cin>>marks[i][j];}
float av[10];
for(i=0;i<10;i++)
{ float sum=0;
sum=sum+marks[i][j];
av[i]=sum/5;}
printing……
وائل قصاص

205. for(int i=0;i<3;i++) for(int j=0;j<4;j++) cin>>A[i][j];
int A[3][4], B[4][3];
for(int i=0;i<3;i++)
for(int j=0;j<4;j++)
cin>>A[i][j];
for(i=0;i<3;i++)
B[ j][i]=A[i][j]
Printing B ……..
وائل قصاص

206. Function to calculate the Transpose of an array 3x4
void trans34(int x[3][4],int y[4][3]) {
for(int r=0;r<3;r++)
for(int c=0;c<4;c++)
y[c][r]=x[r][c]; }
وائل قصاص

207. Homework
1- Write program to compute and print the result of Matrix A[n][n] multiplied by Matrix B[n][n] and store the result within Matrix C[n][n].
2- Write program to Compute and print the result of Matrix A[n][n] multiplied by Vector V[n] and store the result within Vector C[n].
وائل قصاص

208. Second exam topics 1- do-while statement. 2- nested for loop
3- nested while statement
4- math library functions.
5- functions prototype and definitions.
6- rand () and srand() functions
7- scope rules (local, global and static variables)
8- Recursion
9- call by value and reference
10- Inline function
11- :: scope resolution operator.
12- one dim array only ( definition and passing one dim array to a function).
وائل قصاص

209. Strings #include <iostream.h> void main() { char n[10];
char a[10]={'A','h','m','e','d'};
for(int i=0; i<5 ; i++)
cout<<a[i]<<endl; }
وائل قصاص

210. #include <iostream.h> void main() {
char a[10]={'I','b','r','a','h','e','e','m‘};
for(int i=0; a[i]!=0 ; i++)
cout<<a[i]<<endl; }
وائل قصاص

211. #include <iostream.h> void main() {
char a[10]={'A','h','m','e','d'};
for(int i=0; a[i]!=0 ; i++)
{for(int j=0;j<i;j++)
cout<<" ";
cout<<a[i]<<endl; }
وائل قصاص

212. #include <iostream.h> void main() { char a[10]="Ahmed";
for(int i=0; a[i]!=0 ; i++)
{for(int j=0;j<i;j++)
cout<<" ";
cout<<a[i]<<endl; }
وائل قصاص

213. #include <iostream.h> void main() { char a[10];
cout<<"Enter a name : ";
cin>>a;
cout<<a<<endl;
for(int i=0; a[i]!=0 ; i++)
{for(int j=0;j<i;j++)
cout<<' ';
cout<<a[i]<<endl; }
وائل قصاص

214. #include <iostream.h> void main() { char a[10]; char b[10];
cout<<"Enter ur first name : ";
cin>>a;
cout<<"Enter ur second name : ";
cin>>b;
cout<<"Hello "<<a<<" "<<b<<endl;
for(int i=0; a[i]!=0 ; i++)
{for(int j=0;j<i;j++)
cout<<' ';
cout<<a<<endl; }
وائل قصاص

215. #include <iostream.h> void main() { char a[10];
cout<<"Enter a name : ";
cin>>a;
cout<<a<<endl;
for(int i=0; a[i]!=0 ; i++)
{for(int j=0;j<i;j++)
cout<<' '; }
cout<<i<<endl;
وائل قصاص

216. Final exam question
Write a function that returns the length of a string or array of characters.
The function prototype is
int length(char[ ]);
وائل قصاص

217. int length(char name[ ]) { for(int i=0;name[i]!=0;i++) ; return i; }
وائل قصاص

218. Ex: Write a program that prints the name inversed( from the last char to the first character
#include <iostream.h>
void main() {
char name[10];
cout<<"Enter ur name : ";
cin>>name;
for(int i=0; name[i]!=‘\0’ ; i++);
for(int j=i-1;j>=0;j--)
cout<<name[j];
cout<<endl; }
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219. Chapter 5 - Pointers and Strings
Outline
5.1 Introduction
5.2 Pointer Variable Declarations and Initialization
5.3 Pointer Operators
5.4 Calling Functions by Reference
5.7 Pointer Expressions and Pointer Arithmetic
5.8 The Relationship Between Pointers and Arrays
5.9 Arrays of Pointers
5.12 Introduction to Character and String Processing
Fundamentals of Characters and Strings
String Manipulation Functions of the String-handling Library
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220. 5.1 Introduction Pointers Powerful, but difficult to master
Simulate call-by-reference
Close relationship with arrays and strings
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221. 5.2 Pointer Variable Declarations and Initialization
Pointer variables
Contain memory addresses as their values
Normal variables contain a specific value (direct reference)
Pointers contain the address of a variable that has a specific value (indirect reference)
Indirection
Referencing a pointer value
Pointer declarations
* indicates variable is a pointer
int *myPtr;
declares a pointer to an int, a pointer of type int *
Multiple pointers require multiple asterisks
int *myPtr1, *myPtr2;
count 7
count 7
countPtr
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222. 5.2 Pointer Variable Declarations and Initialization
Can declare pointers to any data type
Pointers initialization
Initialized to 0, NULL, or an address
0 or NULL points to nothing
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223. 5.3 Pointer Operators & (address operator)
Returns the address of its operand
Example
int y = 5; int *yPtr; yPtr = &y; // yPtr gets address of y
yPtr "points to" y
yPtr y 5
yptr
500000
600000
address of y is value of yptr
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224. 5.3 Pointer Operators * (indirection/dereferencing operator)
Returns the value of what its operand points to
*yPtr returns y (because yPtr points to y).
* can be used to assign a value to a location in memory
*yptr = 7; // changes y to 7
Dereferenced pointer (operand of *) must be an lvalue (no constants)
* and & are inverses
Cancel each other out
*&myVar == myVar
and
&*yPtr == yPtr
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225. ---------- 10 ---------- ---------- 12FF7C ----------
Pointer
Pointer is a memory location, which contains a memory address of another memory location, which belong to a variable. We say that the pointer points to the variable.
FF7C
12FF7C 12FB8D
a ptr
#include <iostream.h>
void main() {
int a = 10;
int *ptr = &a;
cout<<ptr<<endl;
cout<<&a<<endl;
cout<<*ptr<<endl;
cout<<a<<endl; }
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226. Pointers #include <iostream.h> void main() { int x=5;
int* y; // pointer to an integer
y=&x;
cout<<x<<endl<<&x<<endl;
cout<<y<<endl<<*y<<endl; }
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227. 2 // Using the & and * operators 3 #include <iostream> 4
1 // Fig. 5.4: fig05_04.cpp
2 // Using the & and * operators
3 #include <iostream> 4
5 using std::cout;
6 using std::endl; 7
8 int main()
9 {
10 int a; // a is an integer
11 int *aPtr; // aPtr is a pointer to an integer 12
13 a = 7;
14 aPtr = &a; // aPtr set to address of a 15
16 cout << "The address of a is " << &a
<< "\nThe value of aPtr is " << aPtr; 18
19 cout << "\n\nThe value of a is " << a
<< "\nThe value of *aPtr is " << *aPtr; 21
22 cout << "\n\nShowing that * and & are inverses of"
<< " each other.\n&*aPtr = " << &*aPtr
<< "\n*&aPtr = " << *&aPtr << endl;
25 return 0;
26 }
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228. Output The address of a is 006AFDF4 The value of aPtr is 006AFDF4
The value of a is 7
The value of *aPtr is 7
Showing that * and & are inverses of each other.
&*aPtr = 006AFDF4
*&aPtr = 006AFDF4
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229. Example 1 #include <iostream.h> void main( ) {
int a = 10, b = 20;
int *ptr_a, *ptr_b;
ptr_a = &a;
ptr_b = &b;
cout<<"a="<<*ptr_a<<"b="<<*ptr_b<<endl;
a += 10;
b += 20;
++*ptr_a;
++*ptr_b;
cout<<"a="<<a<<"b="<<b<<endl;
ptr_a = ptr_b;
cout<<"b="<<*ptr_a<<endl; }
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230. Example 2 (String) #include <iostream.h> void main() {
----- A H m a d L i
St_name
#include <iostream.h>
void main() {
char *St_name;
St_name = "Ahmad Ali";
cout<<endl<<St_name<<endl; }
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231. Example 3 (String) #include <iostream.h> void main() {
----- A H m a d L i
St_name[0]
St_name[1]
St_name[2]
St_name[3]
St_name[4]
St_name[5]
St_name[6]
St_name[7]
St_name[8]
#include <iostream.h>
void main() {
char St_name[20];
cout<<"Please enter your name: ";
cin.getline(St_name,20,'\n');
cout<<endl<<St_name<<endl; }
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232. Example 4 (array name is a static pointer)
----- F1
1.2
2.2
3.2
4.2
5.2
Vector
ptr
Vactor[0]
Vactor[1]
Vactor[2]
Vactor[3]
Vactor[4] B1 B2 F1 F2 F3 F4 F5
#include <iostream.h>
void main() {
float Vector[5] = {3.2, 2.2, 6.2, 4.2, 9.2};
float *ptr;
ptr = Vector; // ptr=&Vector[0];
for (int i=0; i<5; i++) {
cout<<"\n"<<*ptr;
++ptr; } }
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233. 5.4 Calling Functions by Reference
Call by reference with pointer arguments
Pass address of argument using & operator
Allows you to change actual location in memory
Arrays are not passed with & because the array name is already a pointer
* operator used as alias/nickname for variable inside of function
void doubleNum( int *number )
{ *number = 2 * ( *number ); }
*number used as nickname for the variable passed in
When the function is called, must be passed an address
doubleNum( &myNum );
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234. 2 // Cube a variable using call-by-reference
1 // Fig. 5.7: fig05_07.cpp
2 // Cube a variable using call-by-reference
3 // with a pointer argument
4 #include <iostream> 5
6 using std::cout;
7 using std::endl; 8
9 void cubeByReference( int * ); // prototype 10
11 int main()
12 {
13 int number = 5; 14
15 cout << "The original value of number is " << number;
16 cubeByReference( &number );
17 cout << "\nThe new value of number is " << number << endl;
18 return 0;
19 } 20
21 void cubeByReference( int *nPtr )
22 {
23 *nPtr = *nPtr * *nPtr * *nPtr; // cube number in main
24 }
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235. The original value of number is 5 The new value of number is 125
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236. 5.7 Pointer Expressions and Pointer Arithmetic
Increment/decrement pointer (++ or --)
Add/subtract an integer to/from a pointer( + or += , - or -=)
Pointers may be subtracted from each other
Pointer arithmetic is meaningless unless performed on an array
5 element int array on a machine using 4 byte ints
vPtr points to first element v[ 0 ], which is at location 3000
vPtr = 3000
vPtr += 2; sets vPtr to 3008
vPtr points to v[ 2 ]
pointer variable vPtr
v[0]
v[1]
v[2]
v[4]
v[3]
3000
3004
3008
3012
3016
location
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237. cout<<*vp<<endl; cout<<*(vp+2)<<endl; vp+=2;
void main( ) {
int v[5]={4,2,7,3,10};
int *vp;
vp=&v[0];
cout<<*vp<<endl;
cout<<*(vp+2)<<endl;
vp+=2;
cout<<*vp; }
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238. cout<<*(vp++)<<endl; }
void main( ) {
int v[5]={5,2,7,3,10};
int *vp;
vp=&v[0];
for(i=0;i<5;i++)
cout<<*(vp++)<<endl; }
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239. vp=v; // v is a pointer to v[0] for(i=0;i<5;i++)
void main( ) {
int v[5]={5,2,7,3,10};
int *vp;
vp=v; // v is a pointer to v[0]
for(i=0;i<5;i++)
cout<<*(vp++)<<endl; }
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240. 5.7 Pointer Expressions and Pointer Arithmetic
Subtracting pointers
Returns the number of elements between two addresses
vPtr2 = v[ 2 ]; vPtr = v[ 0 ]; vPtr2 - vPtr == 2
Pointer comparison
Test which pointer points to the higher numbered array element
Test if a pointer points to 0 (NULL)
if ( vPtr == ‘0’ )
statement
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241. 5.7 Pointer Expressions and Pointer Arithmetic
Pointers assignment
If not the same type, a cast operator must be used
Exception: pointer to void (type void *)
Generic pointer, represents any type
No casting needed to convert a pointer to void pointer
void pointers cannot be dereferenced
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242. 5.8 The Relationship Between Pointers and Arrays
Arrays and pointers closely related
Array name like constant pointer
Pointers can do array subscripting operations
Having declared an array b[ 5 ] and a pointer bPtr
bPtr is equal to b
bptr == b
bptr is equal to the address of the first element of b
bptr == &b[ 0 ]
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243. 5.8 The Relationship Between Pointers and Arrays
Accessing array elements with pointers
Element b[ n ] can be accessed by *( bPtr + n )
Called pointer/offset notation
Array itself can use pointer arithmetic.
b[ 3 ] same as *(b + 3)
Pointers can be subscripted (pointer/subscript notation)
bPtr[ 3 ] same as b[ 3 ]
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244. Arrays and Pointers #include<iostream.h> void main( ) {
int a[10]={1,5, 7, 4, 3, 2, 8, 9, 11, 12};
int *p;
p = a;
for (int i=0; i<10; i++)
cout<<a[i]<<endl; // الطريقة التقليدية لطباعة المصفوفة
cout<<endl;
for (i=0; i<10; i++)
{ cout<<*p<<endl; // طريقة لطباعة المصفوفة عن باستخدام العناوين
p++; } }
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245. #include<iostream.h> void main( ) {
int a[10]={1,5, 7, 4, 3, 2, 8, 9, 11, 12};
int *p;
p = a;
for (int i=0; i<10; i++)
cout<<a[i]<<endl;
cout<<endl;
for (i=0; i<10; i++)
cout<<*(p+i)<<endl; // نفس المثال السابق ولكن بدون تعديل قيمة المؤشر }
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246. Example 2: Write a program to compare two arrays if they are equivalent or not.
#include <iostream.h>
void main( )
{int a[5]={1, 3, 5, 7, 9};
int b[5]={1, 3, 5, 8, 9};
bool flag=true;
for (int i=0; i<5; i++) {
if (*(a+i)!=*(b+i)) // تكافئ if(a[i] != b[i])
{ flag = false; break; } }
if (flag)
cout<<"Two arrays are equivalent ";
else
cout<<"Two arrays are not equivalent";
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247. Difference between arrays of char and arrays of int
#include <iostream.h>
void main() {
char a[10]="Ahmad"; // prints Ahmed
cout<<a<<endl;
int b[10]={1,2,3,4,5};
cout<<b<<endl; // prints the address of
//the first element in the array }
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248. #include <iostream.h> void main() {
char a[10]="Ahmad"; // prints Ahmed
cout<<a<<endl;
int b[10]={1,2,3,4,5};
cout<<b<<endl; // prints the address of
//the first element in the array
int x=5;
int* y; // pointer to an integer
y=&x;
cout<<x<<endl<<&x<<endl;
cout<<y<<endl<<*y<<endl; }
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249. 5.9 Arrays of Pointers Arrays can contain pointers
Commonly used to store an array of strings
char *suit[ 4 ] = {"Hearts", "Diamonds", "Clubs", "Spades" };
Each element of suit is a pointer to a char * (a string)
The strings are not in the array, only pointers to the strings are in the array
suit array has a fixed size, but strings can be of any size
suit[3]
suit[2]
suit[1]
suit[0]
’H’
’e’
’a’
’r’
’t’
’s’
’\0’
’D’
’i’
’m’
’o’
’n’
’d’
’C’
’l’
’u’
’b’
’S’
’p’
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250. 5.12.1 Fundamentals of Characters and Strings
Character constant
Integer value of a character
Single quotes
'z' is the integer value of z, which is 122
String
Series of characters treated as one unit
Can include letters, digits, special characters +, -, * ...
String literal (string constants)
Enclosed in double quotes, for example:
"I like C++"
Array of characters, ends with null character '\0'
Strings are constant pointers (like arrays)
Value of string is the address of its first character
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251. 5.12.1 Fundamentals of Characters and Strings
String assignment
Character array:
char color[] = "blue";
Creates 5 element char array, color, (last element is '\0')
variable of type char *
char *colorPtr = "blue";
Creates a pointer to string "blue", colorPtr, and stores it somewhere in memory
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252. 5.12.1 Fundamentals of Characters and Strings
Reading strings
Assign input to character array word[ 20 ]
cin >> word
Reads characters until whitespace or EOF
String could exceed array size
cin >> setw( 20 ) >> word;
Reads 19 characters (space reserved for '\0')
cin.getline
Reads a line of text
Using cin.getline
cin.getline( array, size, delimiter character);
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253. 5.12.1 Fundamentals of Characters and Strings
cin.getline
Copies input into specified array until either
One less than the size is reached
The delimiter character is input
Example
char sentence[ 80 ];
cin.getline( sentence, 80, '\n' );
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254. 5.12.2 String Manipulation Functions of the String-handling Library
String handling library <cstring> provides functions to
Manipulate strings
Compare strings
Search strings
Tokenize strings (separate them into logical pieces)
ASCII character code
Strings are compared using their character codes
Easy to make comparisons (greater than, less than, equal to)
Tokenizing
Breaking strings into tokens, separated by user-specified characters
Tokens are usually logical units, such as words (separated by spaces)
"This is my string" has 4 word tokens (separated by spaces)
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255. 5.12.2 String Manipulation Functions of the String-handling Library
char *strcpy( char *s1, const char *s2 );
Copies the string s2 into the character
array s1. The value of s1 is returned.
char *strncpy( char *s1, const char *s2, size_t n );
Copies at most n characters of the string s2 into the character array s1. The value of s1 is returned.
char *strcat( char *s1, const char *s2 );
Appends the string s2 to the string s1. The first character of s2 overwrites the terminating null character of s1. The value of s1 is returned.
char *strncat( char *s1, const char *s2, size_t n );
Appends at most n characters of string s2 to string s1. The first character of s2 overwrites the terminating null character of s1. The value of s1 is returned.
int strcmp( const char *s1, const char *s2 );
Compares the string s1 with the string s2. The function returns a value of zero, less than zero or greater than zero if s1 is equal to, less than or greater than s2, respectively.
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256. 5.12.2 String Manipulation Functions of the String-handling Library (III)
int strncmp( const char *s1, const char *s2, size_t n );
Compares up to n characters of the string s1 with the string s2. The function returns zero, less than zero or greater than zero if s1 is equal to, less than or greater than s2, respectively.
char *strtok( char *s1, const char *s2 );
A sequence of calls to strtok breaks string s1 into "tokens"—logical pieces such as words in a line of text—delimited by characters contained in string s2. The first call contains s1 as the first argument, and subsequent calls to continue tokenizing the same string contain NULL as the first argument. A pointer to the current to­ken is returned by each call. If there are no more tokens when the function is called, NULL is returned.
size_t strlen( const char *s );
Determines the length of string s. The number of characters preceding the terminating null character is returned.
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257. String Functions
To use string functions we must include the <cstring> library or <string.h> library in the top of the program
#include <cstring>
String functions that we will cover are:
strcpy
strncpy
strcat
Strncat
Strcmp
Strncmp
strlen
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258. Example on strcpy, strncpy
#include <iostream.h>
#include<string.h>
void main( ) {
char x[ ]="Happy Birthday to You";
char y[25];
char z[15];
strcpy(y, x);
cout<<x<<" "<<y<<endl;
strncpy(z, x,14);
z[14]='\0'; // strncpy doesn’t add \0 at the end
cout<<z<<endl; }
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259. Output Happy Birthday to You Happy Birthday to You Happy Birthday
Press any key to continue
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260. Example on strcat, strncat
#include <iostream.h>
#include<string.h>
void main( ) {
char s1[20]="Happy";
char s2[ ]="New Year";
char s3[40]=""; // this puts \0 in the whole array
cout<<s1<<" "<<s2<<endl;
strcat(s1, s2);
strncat(s3, s1, 5);
cout<<s1<<" "<<s3<<endl;
strcat(s3, s1); }
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261. Output Happy New Year HappyNew Year New Year HappyNew Year Happy
HappyNew Year HappyHappyNew Year
Press any key to continue
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262. #include <iostream.h> #include<string.h> void main( ) {
char s1[ ]="Happy New Year";
char s2[ ]="Happy New Year";
char s3[ ]="Happy Holidays";
cout<<s1<<"\n"<<s2<<"\n"<<s3<<"\n";
cout<<strcmp(s1, s2)<<"\n"
<<strcmp(s1, s3)<<"\n"
<<strcmp(s3, s1)<<endl;
cout<<strncmp(s1,s3,6)<<"\n"
<<strncmp(s1, s3, 7)<<"\n"
<<strncmp(s3, s1,7)<<endl; }
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263. Output Happy New Year Happy Holidays 1 -1 Press any key to continue1 -1
Press any key to continue
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