1. Object-Oriented Programming in C++
Lecture 1
Introduction

2. Introduction Staff Information Module Blackboard site Fred Pratt K319
Cathy French K233
Module Blackboard site
Module Information
Descriptor
Timetable - 9 lectures + 9 practicals, plus revision/test preparation in Week 4
Assessment – portfolio test
Resources – Visual Studio
Books
Study Space – lecture slides and practical exercises

3. Assumptions you have studied programming before you are new to C++
Java, C, algorithms, object-orientation
you are new to C++
have you studied UML diagrams?

4. Why learn C++? one of the most widely used programming languages
C++ applications are everywhere
embedded systems, operating systems, games, real-time systems, servers, applications
closely maps to hardware instructions
strongly typed, supports OO programming
but unlike C# and Java, not every variable and function needs to belong to a class
flexible, efficient, stable
related to other commonly-used languages
C, C#, Java

5. Computer Science jobs http://www. itjobswatch. co
For the 6 months to 29 June 2011, IT jobs within the UK citing Computer Science also mentioned the following programming languages in order of popularity.
The figures indicate the number of jobs and their proportion against the total number of IT job ads sampled that cited Computer Science.
(36.01 %) Java
(29.35 %) C#
(27.76 %) SQL
(24.63 %) C++
(20.54 %)JavaScript
(12.82 %) C
(9.340 %) PHP
(8.264 %) Python
(6.452 %) Perl
(4.149 %) Ruby
(4.030 %) VB.NET
(3.675 %) T-SQL
(2.786 %) VB
(2.337 %) Shell Script
(2.168 %) Objective-C

6. Early programming languages
Simula
Lisp
Algol60
Algol68
Fortran
Pascal
BCPL
Classic C
COBOL
PL\1
Red==major commercial use Yellow==will produce important “offspring” 6
Stroustrup/Programming

7. Modern programming languages
Lisp
Python
Smalltalk
PHP
Fortran77
Java95
Java04
Eiffel
Simula67
C89
C++
C++98
C++0x
Ada
Ada98 C#
Object Pascal
Pascal
Javascript
COBOL04
COBOL89
Visual Basic
PERL
Stroustrup/Programming 7

8. Hello World #include <string> #include <iostream>
using namespace std;
int main() {
string name;
cout << "What is your name? ";
cin >> name;
cout << "Hello, " << name << "!" << endl;
return 0; }
How does this compare to Java? C? C#?

9. Comparison to Java main method syntax #include directive
no parameter
returns an int
0 for success – can omit
syntax
brackets, semicolons, variables
#include directive
copy the contents of the named file here
using statement
use a C++ namespace without qualification
similar to importing a Java package

10. string part of the standard library namespace string is a class
like String in Java
unlike C-style strings
null-terminated character array
has useful methods
s.size() s.length()
s.insert(pos, x) s.append(pos, x)
s.erase(pos) pos = s.find(x)

11. C++ primitive types Type Name Bytes Other Names Range of Values int 4
signed
–2,147,483,648 to 2,147,483,647
bool 1
none
false or true
char
–128 to 127 by default
signed char
–128 to 127
unsigned char
0 to 255
short 2
short int, signed short int
–32,768 to 32,767
long
long int, signed long int
long long 8
–9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
float
3.4E +/- 38 (7 digits)
double
1.7E +/- 308 (15 digits)
wchar_t
__wchar_t
0 to 65,535
size is implementation-dependant
table is from MSDN and refers to Microsoft Visual C++

12. Input and output defined in iostream library
cin is the standard input stream
from keyboard
cout is the standard output stream
to console window
the streams contain a sequence of characters
cin >> name;
puts the characters in the input stream into the variable name
cout << name;
puts the characters in the variable name into the output stream

13. << and >> operators
<< sends bytes to an output stream object
insertion operator
works for all standard C++ data types
can concatenate output
cout << "Hello, " << name << "!" << endl;
endl replaces the C endline character '\n'
>> reads bytes from the input stream
up to a whitespace character
use istream::getLine() function to read multiple words
getline(cin, name);

14. C++ operators similar to Java and C need to know precedence
the same operator can have a different meaning depending on the operand type
<<
operator overloading
when we define C++ classes we can define our own operator overload
be sensible!

15. C++ constructs
sequence, selection, iteration constructs are the same as in Java, C and C#
unlike C, can declare variables anywhere within a block
doesn't need to be at the beginning
C++ for loop
for (int i=0; i < 5; i++) {
cout << "Hello, " << "!" << endl; }

16. Example – read-ahead while loop
int sum=0;
int x;
cin >> x;
while (x!=-9999) {
sum=sum+x; }
cout << "The sum is " << sum << endl;

17. multiway if- example int x = 8; if ( x <= 5)
cout << "The number is small: ";
else if (x <= 10)
cout << "The number is medium: ";
else
cout << "The number is big: ";
cout << x << endl
The number is medium: 8

18. C++ bool be careful with boolean operations int x = 5;
C++ has a bool data type
but integers and booleans are interchangeable (like C)
0 is false, non-zero is true
false is 0, true is 1
== comparison operator = assignment operator
int x = 5;
if (x) true (x is non-zero)
if (x==4) false (x is 5)
if (x=4) true (x is now set to 4, which is non-zero)

19. Summary
Today we have introduced the C++ language and compared it to other languages
same data types and operators
but their size can vary between C++ implementations
program structure is similar
input and output uses iostream
sequence, selection, iteration constructs are the same as in Java, C and C#
Practical exercises:
getting started with Visual Studio and C++
a few simple C++ programs

20. Further reading “C++: A beginners guide” by Herbert Schildt
string library
fundamental types
C++ operators