Computer Programming -1Lecture 7
Conditional Statements
1- if Statement .
2- if ….. else Statement .
3- switch .
A- If …… statement
- The if statement is used to check a condition and if the
condition is true, we run a block of statements
Syntax :
1\
If ( condition )
{
statement
}
example:
if (x>y)
cout<<"X is greater than Y“ ;
- program to enter number, and print message if the number
>=100
#include<iostream.h>
int main( )
{
int x;
cout<<"enter x:";
cin>>x;
if ( x>=100)
cout<<"large value";
return 0;
}
2\
if (condition)
{
Statement 1;
Statement 2;
…..…………
Statement n;
}
example:
if (x>y)
{
cout<<"big number is:" <<x;
cout<<"\n small number is:" <<y;
}
- This program to increase the salary of the employee 10% if its salary less than
or equal 300 or its rank greater than or equal 4
#include <iostream.h>
int main()
{
int rank;
float salary;
cout<<"Enter the salary and rank:";
cin>>salary>>rank;
if ((salary<=300)||(rank>=4))
{
salary=salary*0.010;
cout<<"salary after increasing \n";
cout<<salary<<endl;
}
return 0;
}
B- if…….. else Statement
used to check a condition and if the condition is true, we run a block
of statements, else we process another block of statements .
Syntax :
if (condition)
statement;
else
statement;
example:
if(x==100)
cout<<"x is 100";
else
cout <<"x is not 100";
This program determine if the entered number is even or odd ..
#include <iostream.h>
int main()
{
int a;
cout<<"Enter the number:";
cin>>a;
if (a%2= =0)
cout<<" the number is even";
else
cout<<"the number is odd";
return 0;
}
- Write a program read tow numbers and determine which number
is the greatest ..
#include <iostream.h>
int main()
{
int a,b;
cout<<"Enter tow different number:";
cin>>a>>b;
if (a>b)
cout<<a<<" number is greater "<<b;
else
cout<<b<<" number is greater "<<a;
return 0;
}
(Nested if) complex if statement
if (number > 0)
{
if (number > 5)
cout<<"the number is greater than 5";
else
out<<" the number is less than 5";
}
if ( (number > 0) && if (number > 5) )
{
cout<<"the number is greater than 5";
else
cout<<" the number is less than 5";
}
‫ الى‬else ‫تعود‬
if(number>5)
- This program determine if the entered number is
even or odd..
#include<iostream.h>
int main()
{
int number;
cin>> number;
if (number>0)
if (number%2==0)
cout<<"the number is positive even";
else
cout<<" the number is positive Odd";
else
cout<<"the number is less than zero";
}
‫ األخيرة الى‬else ‫تعود‬
if(number>0)
if – else – if
Syntax :
if (condition1)
statement1;
else
if(condition2)
statement2;
else
if(condition3)
statement3;
……
……
else
if(condition n)
statement n;
else
statement;
#include <iostream.h>
Example
int main()
{
int n;
cout << " Enter the number: ";
cin >> n;
if (n== 1)
cout << " Sunday : Programming(1) " <<endl ;
else if (n== 2)
cout << " Monday : English " << endl ;
else if (n== 3)
cout << " Tuesday : Introduction" << endl;
else if (n== 4)
cout << " Wednesda y: Math " << endl;
else if (n== 5)
cout << " Thursday : Islamic " << endl;
else
cout << " nothing " <<endl ;
return 0;
}
Write a C++ program by using if statement To simulate the calculator such that when
you enter tow numbers and the mathematical operation(+,-,*,%,\) you get a result ?
#include <iostream.h>
int main()
{
double a ,b ;
char x ;
cout << "enter the operation : " ;
cin >> a >>x >> b ;
if (x=='+')
cout << " a+b = " << a+b << endl ;
else if (x=='-')
cout<< "a-b = " << a-b << endl ;
else if (x=='*')
cout << "a*b = " << a*b << endl ;
else if (x=='/')
cout << "a/b = " << a/b << endl ;
else
cout << "Unknown operation" << endl ;
return 0;
}
Write a C++ program by using if statement to calculate the grades of
students ?
#include <iostream.h>
int main()
{
float score ;
cout << "Enter your score : ";
cin >> score ;
if (score >= 90)
cout << "Your Grade is A " << endl;
else if (score >= 80)
cout << "Your Grade is B " << endl ;
else if (score >= 70)
cout << "Your Grade is C " << endl ;
else if (score >= 60)
cout << "Your Grade is D " << endl ;
else if (score >= 0)
cout << "Your Grade is F " << endl ;
else
cout << "Error: Score can't be less than 0 " << endl ;
return 0;
}
Switch statement
A switch statement allows a variable to be tested for
equality against a list of values. Each value is called a
case, and the variable being switched on is checked for
each case.
Switch statement
Syntax
Switch (Expression or variable)
{
case constant 1 :
statement 1;
break;
case constant 2 :
statement 2;
break;
…….
case constant x :
statement x;
break;
default :
statement;
}
Example
switch (x)
{
case 0 :
cout << "Zero !" << endl;
break;
case 1 :
cout << "One !" << endl;
break;
case 2 :
cout << "Two !" << endl;
break;
default :
cout << "Error !" << endl;
}
- Write a C++ program by using switch statement To simulate the calculator
such that when you enter tow numbers and the mathematical operation (+,,*,\) you get a result ?
#include<iostream.h>
int main()
{
float x , y ;
char op ;
cout<< " enter first number and math operator and second number : " ;
cin >> x >> op >> y ;
switch (op)
{
case '+' :
cout<< "x+y = " << x+y << endl ;
break ;
case '-' :
cout<< "x-y = " << x-y << endl ;
break ;
case '*' :
cout<< "x*y = " << x*y << endl ;
break ;
case '/ ' :
cout<< "x/y = " << x/y << endl ;
break ;
default :
cout << " incorrect operation " << endl ;
}
return 0 ;
}
- Write a C++ program by using switch statement to print the name of the
color depending on the character input.
#include<iostream.h>
int main()
{
char c ;
cout<< " enter character : " ;
cin >> c ;
switch (c)
{
case 'b' :
cout << "blue" << endl ;
break ;
case 'g' :
cout << "green" << endl ;
break ;
case 'r' :
cout << "red" << endl ;
break ;
case 'w' :
cout << "white" << endl ;
break ;
default :
cout << " unknown char " << endl ;
}
return 0 ;
}
- Write a C++ program by using switch statement to print the days of the week.
#include<iostream.h>
int main()
{
int weekday ;
cout<< " enter number : " ;
cin >> weekday ;
switch (weekday)
{
case 1 :
cout<< "Saturday" << endl ;
break ;
case 2 :
cout<< "Sunday" << endl ;
break ;
case 3 :
cout<< "Monday" << endl ;
break ;
case 4 :
cout<< "Tuesday" << endl ;
break ;
case 5 :
cout<< "Wednesday" << endl ;
break ;
case 6 :
cout<< "Thursday" << endl ;
break ;
case 7 :
cout<< "Friday" << endl ;
break ;
default :
cout << " unknown char " << endl ;
}
return 0 ;
}