1. Intro to Programming Week # 2 Variables/Data type Lecture # 4 & 5
Department of Computer Science & Engineering
Air University
Intro to Programming Week # 2 Variables/Data type Lecture # 4 & 5
By: Saqib Rasheed

2. A First Program - Greeting.cpp
// Author Saqib Rasheed
#include <iostream>
using namespace std;
int main() {
cout << "Hello world!";
return 0; }
By Saqib Rasheed

3. Greeting Output
By Saqib Rasheed

4. Whitespace
#include <iostream> using namespace std; int main () { cout << “Hello word!\n” ; return 0;}
By Saqib Rasheed

5. C++ Programming Basics by Robert Lafore
Reference Chapter # 2:
C++ Programming Basics by
Robert Lafore
By Saqib Rasheed

6. Escape Sequence
Escape sequences are used to represent certain special characters within string literals and character literals.
\n new line
\t horizontal tab (8 spaces)
\’ single quote
\” double quote
\? question mark
\v vertical tab
\a audible bell
By Saqib Rasheed

7. Example # 2 #include <iostream> using namespace std;
int main ( ) {
cout << “\t Welcome to Air University \n“;
cout<<“ \n\t School of Engineering”;
cout<<“it can be\n used \t between\n the string”;
return 0; }
New Line
Tab
By Saqib Rasheed

8. Variables
A storage box, its type defines the kind of stuff you store in it
E.g. shoe box  used for shoes
Jewelry box  used for jewelry
CD kit  used for CDs
By Saqib Rasheed

9. Variable Variable is a box
In computer, a storage box is a memory location on RAM
By Saqib Rasheed

10. Each little box is a memory location
Memory in Computer
Each little box is a memory location
First you ask computer to give you a box and you also have to specify what type of box you want
Occupied Memory Spaces
Free
Memory Spaces
By Saqib Rasheed

11. Asking for Memory Type of Box box name;
Type is a bit messy, it can’t be shoe box or jewelry
Could be anything, alpha, bravo, charlie
Some rules apply 
integer
character
double
float
bool (etc)
By Saqib Rasheed

12. Rules for Variable name
Rules to Write Variable.
First Letter is always Character
Underscore _ (Not Recommended)
Can’t use real numbers (Syntax Errorr)
int num1;
By Saqib Rasheed

13. Rules for Variable name
In a program a variable has:
Name
Type
Size
Value
int num = 10;
Assignment Operator
By Saqib Rasheed

14. Rules of variables int n1; int n1,n2,n3; int n1; int n2; int n3;
float a1; int b1; double c1;
By Saqib Rasheed

15. Type Size (bytes) Range-Minimum Range- Maximum
Character Unsigned Char Signed Char Integer ,147,483,648 2,147,483,647 Signed Int ,4294,967,295 Unsigned Int ,147,483,648 2,147,483,647 Short Int ,768 32,767 Signed short Int ,535 Unsigned Short Int ,768 32,767 Long Int ,147,483,648 2,147,483,647 Signed Long Int ,294,967,295 Unsigned Long Int 8 -2,147,483,648 2,147,483,647 Float E E+38 Double E E+308 Long Double E E+308 Bool 1 True/False
By Saqib Rasheed

16. How To get Value from User
How to get value from user we use
cin>>x;
Also defined in <iostream> library file

17. Displaying age
#include<iostream> using namespace std; int main (){ float a1,a2; cout<<“Enter age for student 1=”; cin>>a1; cout<<“Enter age for student 2=”; cin>>a2; cout<<a1; cout<<a2; return 0; }
By Saqib Rasheed

18. Displaying age
#include<iostream> using namespace std; int main (){ float a1,a2; cout<<“Enter age for student 1=”; cin>>a1; cout<<“Enter age for student 2=”; cin>>a2; cout<<“\nAge of Student 1 = ”<<a1; cout<<“\nAge of Student 2 = ”<<a2; return 0; }
By Saqib Rasheed

19. Displaying age
#include<iostream> using namespace std; int main (){ float a1,a2; cout<<“Enter age for student 1=”; cin>>a1; cout<<“Enter age for student 2=”; cin>>a2; cout<<“\nAge of Student 1 = ”<<a1; cout<<“\nAge of Student 2 = “ <<a2; return 0; }
By Saqib Rasheed

20. Displaying age
#include<iostream> using namespace std; int main (){ float a1,a2; cout<<“Enter age for student 1=”; cin>>a1; cout<<“Enter age for student 2=”; cin>>a2; cout<<“\nAge of Student 1 = ”<<a1; cout<<“\nAge of Student 2 = “; cout <<a2; return 0; }
By Saqib Rasheed

21. Average age Example
#include<iostream> using namespace std; int main (){ float a1,a2,a3,a4,a5; cout<<“Enter age for student 1=”; cin>>a1; cout<<“Enter age for student 2=”; cin>>a2; : float sum, avg; sum = a1+a2+a3+a4+a5; Avg = sum / 5; cout<<“Average age = ”<<avg; return 0; }
By Saqib Rasheed

22. Arithmetic Operators Common Addition + Subtraction - Multiplication *
Division /
Mod %
Write m*x + b not mx + b
By Saqib Rasheed

23. Integer Division Integer division produces an integer result Examples
Truncates the result
Examples
3 / 2 evaluates to 1
4 / 6 evaluates to 0
10 / 3 evaluates to 3
By Saqib Rasheed

24. Mod Produces the remainder of the division Examples
5 % 2 evaluates to 1
12 % 4 evaluates to 0
4 % 5 evaluates to 4
By Saqib Rasheed

25. Operators and Precedence
Consider mx + b
Consider m*x + b which of the following is it equivalent to
(m * x) + b
m * (x + b)
Operator precedence tells how to evaluate expressions
Standard precedence order
() Evaluate first, if nested innermost done first
* / % Evaluate second. If there are several, then evaluate from left-to-right
+ - Evaluate third. If there are several, then evaluate from left-to-right
By Saqib Rasheed

26. Operator Precedence Examples 20 - 4 / 5 * 2 + 3 * 5 % 4 (4 / 5)
/ 5 * * 5 % 4
(4 / 5)
((4 / 5) * 2)
((4 / 5) * 2) (3 * 5)
((4 / 5) * 2) ((3 * 5) % 4)
(20 -((4 / 5) * 2)) ((3 * 5) % 4)
(20 -((4 / 5) * 2)) + ((3 * 5) % 4)
By Saqib Rasheed

27. Write Code for this equation
Precedence 4 3
X = * 6 ( 10 – 2 ) / 10
Y = 10 / 5 * 2 ( ) + 6
Write Code for this equation 5 2 1
By Saqib Rasheed

28. Quadratic Equation In algebra In C y = ax2 + bx + c
y = a*x*x + b*x + c
By Saqib Rasheed

29. #include <iostream> using namespace std int main ( ) { int x ;
int y ;
int z ;
x = 10 ;
y = 20 ;
z = x + y ;
cout << " x = " ;
cout << x ;
cout<< " Y = " <<y;
cout << " z =x + y " << x+y ; }
By Saqib Rasheed

30. Declaration of Variables
int x, y, z ;
int x; int y; int z ;
char n1, n2 = ‘a’;
float num1, num2 = 30.8, n3;
double n3;
By Saqib Rasheed

31. Calculator Code
#include <iostream> using namespace std int main ( ) { int num1, num2, res; cout<<“Enter Number 1 =”; cin>>num1; cout<<“Enter Number 2 =”; cin>>num2; res = num1 + num2; cout<<“Addition Result = ”<<res; res = num1 - num2; cout<<“Subtraction Result = ”<<res; res = num1 * num2; cout<<“Multiplication Result = ”<<res; res = num1 / num2; cout<<“Division Result = ”<<res; res = num1 % num2; cout<<“Modulation Result = ”<<res; }

32. Assignment # 1 Get five equations and write code for each equation
The depth of equation should be at least 6 numbers
Get these numbers from user (Key board)
Display the equation properly (Before )
Display the Result
Instructions
Individual assignment
Due date is next class
Copied assignments will be marked zero
Late assignments not accepted
Submit hard copies along with out put (Screen Shots)
By Saqib Rasheed

33. C++ Programming Basics by Robert Lafore
Reference Chapter # 2:
C++ Programming Basics by
Robert Lafore
By Saqib Rasheed