6. Conditional Statements

●  Conditional Statements:-

                The if, if...else and nested if...else statement are used to make one-time decisions in C++ Programming, that is, to execute some code/s and ignore some code/s depending upon the test condition. Without decision making, the program runs in similar way every time. Decision making is an important feature of every programming language using C++ programming. 

1) Simple if Statement:- 

               The if statement checks whether the test condition is true or not. If the test condition is true, it executes the code/s inside the body of if statement. But it the test condition is false, it skips the code/s inside the body of if statement. 

Structure of if Statement:- 

if (Boolean Expresson) 

{ 

/* if Expression is true */ 

Statements; 

} 

● Flowchart of if :-

Example program:-

#include <iostream.h>

#include <conio.h>

Void main () 

{

       int a=10; 

       if (a>5) 

      { 

             cout<<"if Condition is Satisfied\n";  

             cout<<"a is greater than 5\n";

      }

      cout<<"Value of a is: "<<a<<endl;

      getch();

}

Output:-

if Condition is Satisfied

a is greater than 5

Value of a is:10

2) if...else Statement:-

           The if...else executes body of if when the test expression is true and executes the body of else if 

test expression is false.

Structure of if… else Statement:-

if(Test expression)

{

true block Statements…

}

else

{

false block Statements….

}

         The if statement checks whether the test expression or condition is true or not. If the test 

condition is true, it executes the code/s inside the body of if statement. But it the test condition 

is false, it executes the code/s inside the body of else.

●Flowchart of if...else:-

Example Program:- 

#include <iostream.h>

#include <conio.h> 

void main() 

{ 

         int n; 

         clrscr(); 

         cout<<("Enter The Number \n"); 

         cin>>n; 

         if(n%2==0) 

                 cout<<("Number is Even "); 

         else 

                 cout<<("Number is Odd"); 

         getch(); 

} 

Output:- 

Enter the Number 

7 

Number is Odd

3) Nested if...else Statement:-

             Nested if...else are used if there are more than one test expression. 

Structure of Nested if….else:- 

if(Test expression) 

{ 

        Statement… 

} 

else if(Test expression) 

{ 

        Statements…. 

} 

else 

{ 

        Statements…. 

} 

           The nested if...else statement has more than one test expression. If the first test expression is true, it executes the code inside the braces{ } just below it. But if the first test expression is false, it checks the second test expression. If the second test expression is true, if executes the code inside the braces{ } just below it. This process continues. If all the test expression are false, code/s inside else is executed and the control of program jumps below the nested if...else 

Example Program:- 

#include <iostream.h> 

#include <conio.h>

int main() 

{ 

           int n;

           cout<< "Enter an integer: ";

           cin>> n;

           if ( n>0)

          {

                    cout << "You entered a positive integer"<<endl;

          }

          else if(n<0)

         {

                   cout<<"You entered a negative integer"<<endl;

         }

         else

        {

                   cout<<"You Entered Zero";

        }

        getch();

}

Output:-

Enter an integer

5

You entered Positive integer.

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