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1 Demo Reading Assignments Important terms & concepts Fundamental Data Types Identifier Naming Arithmetic Operations Sample Programs CSE 20232 Lecture 3 – Data Types & Algorithms

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2 Demo Create symbolic link to your dropbox ln –s /afs/nd.edu/coursefa.06/cse/cse20232.01/dropbox/your_afs id/hw1 mydropbox Submit your assignment Using cp command cp hw1_1.cpp mydropbox/hw1 Using WebFile “Check” hw1_1.cpp and click copy follow links opening folder AFS Home, then mydropbox and then hw1 “click” copy again and you are done

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3 Reading Assignments Continue reading in Deitel … Week 2 Sections 2.5-2.7, 6.1-6.6 Appendices B, C, E.1-E.2 Week 3 Sections 4.1-4.12, 15.1-15.8 Appendices F.1-F.3

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4 Important Terms & Concepts Declaration Definition of the type and name of some program element int sum; Statement Line of code causing some action to occur cout << “hello world!” << endl; Literal A value, literally 237 “Sum = “

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5 Important Terms & Concepts Variable (or object) A named program element containing a value that can be changed int x, y, sum; Symbolic Constant A named value that remains constant throughout its existence const int MAX = 32; #define PI 3.14159 Keyword Predefined names in C/C++ having a meaning that cannot be changed int, if, while

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6 Important Terms & Concepts Data Types Types of values that may be used in C++ programs (some predefined, some user-defined) int, float, char, string, complex, … Assignment Setting of the value of a named object/variable x = 25.5; Expression Sequence of code that computes a value a*x*x + b*x +c;

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7 Important Terms & Concepts Cast Explicit change in data type (int) x Coercion Implicit/forced change in data type Precedence Relative ordering of operators, determining the order in which the operations are performed

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8 Fundamental Data Types Boolean type bool true, false Character types char 0..255 : single byte interpreted as ASCII character wchar_t Multiple bytes for representing Unicode characters

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9 Fundamental Data Types Integer types signed char, short int, int, long int In order by increasing range of values and memory size -128.. 127 -32,768.. 32,767 -2,147,483,648.. 2,147,483,648 unsigned char, unsigned short int, unsigned int, unsigned long int 0.. 255, 0.. 65,535, 0.. 4,294,967,295

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10 Fundamental Data Types Floating Point types (real numbers) float double long double In order by increasing magnitude, precision and memory size Float +/- x.xxxxx * 10 +/-37 Double +/- x.xxxxxxxxx * 10 +/-37

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11 Identifier Names Identifiers are names of variables, objects, classes, functions, constants, … A valid C/C++ identifier May contain letters, numerical digits, and underscores Must begin with a letter or underscore Examples Good: firstName, sum, vector1, last_name Bad: 12th_digit, half-way, %interest

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12 Assignments Assigns the value of the right hand side to the object on the left hand side of the operator int x; double y, z; x = 1; // assign x the value 1 y = 5.75; // assign y the value 5.75 z = x + y; // assign z the sum x+y // add the product x*y to the current value of // z and sets z’s new value to the result z = z + x * y;

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13 Integer Arithmetic Given:int x = 23; Addition: x + 5 equals 28 Subtraction: x – 5 equals 18 Multiplication: x * 5 equals 115 Division (quotient): x / 5 equals 4 Division (remainder): x % 5 equals 3 (* / %) have higher precedence than (+ -) Evaluation is left to right in absence of parentheses

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14 Floating Point Arithmetic Givendouble x = 23.5; Addition: x + 5.0 equals 28.5 Subtraction: x - 5.0 equals 18.5 Multiplication: x * 5.0 equals 117.5 Division: x / 5.0 equals 4.7 (* /) have higher precedence than (+ -) Evaluation is left to right in absence of parentheses

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15 Order of Evaluation Basic order is left to right Precedence of operators is set High to low is generally Multiplicative operators (* / %) Additive operators (+ -) Comparisons ( = == !=) Logical operators (&& ||) Complete list is in Appendix A of textbook Parentheses ( ) can be used to alter order of evaluation

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16 Sample Program – circle.cpp // circle.cpp – JHS - compute circumference & area // of circle, given its radius #include #define PI 3.14159 using namespace std; int main () { double radius, area, circ; cout << “Enter radius of circle: “; cin >> radius; circ = 2.0 * PI * radius; area = PI * radius * radius; cout << “Circumference = “ << circ << “ Area = “ << area << endl; return 0; }

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17 Sample Program – circle2.cpp // circle2.cpp – JHS - compute circumference & area // of circle, given its radius (formatted output) #include #include // for I/O manipulators #define PI 3.14159 using namespace std; int main () { double radius, area, circ; cout << “Enter radius of circle: “; cin >> radius; circ = 2.0 * PI * radius; area = PI * radius * radius; cout << fixed << setprecision(3) << “Circumference = “ << circ << “ Area = “ << area << endl; return 0; }

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18 Sample Program – disk.cpp // disk.cpp – JHS - compute surface area and volume of disk, given its radius and thickness #include #include // for I/O manipulators const double PI = 3.14159; // PI value defined differently using namespace std; int main () { double radius, thickness, area, volume; cout << “Enter radius and thickness of disk: “; cin >> radius >> thickness; area = PI * radius * radius; volume = (2.0 * area) + (2.0 * PI * radius * thickness); cout << fixed << setprecision(3) << “Area = “ << area << “ Volume = “ << volume << endl; return 0; }

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