Loops in C++

The looping statements available in C++ are : 

1. For loop 

2. While loop 

3. Do .. While loop

For Loop

For loop can be used in C++ programming to repeat a specific execution for specific number of times.

Example:

#include < iostream >

using namespace std; 

int main() 

{ 

    int a; 

    for (a=1; a<=5; a++) 

    { 

            cout << "The value of a is: " << a << endl;

     }

}

Output:

The value of a is: 1

The value of a is: 2

The value of a is: 3

The value of a is: 4

The value of a is: 5

While Loop

While loop can be used when you want to a statement to execute continuously till the condition specified is true. 

The difference between for loop and while loop is with for loop, you will know how many times the loop will execute.

With while loop, you will not know the number of iterations till the program exits from the loop when the condition does not match.

Example:

#include 

using namespace std; 

int main() 

{ 

    int a = 1 ; 

    while ( a<=5 ) 

    { 

            cout << " The value of a is: " << a << endl; 

            a++; 

     } 

} 

Output:

The value of a is: 1

The value of a is: 2

The value of a is: 3

The value of a is: 4

The value of a is: 5

Do .. While Loop 

The basic difference between for loop, while loop and do while loop is that in do while loop, the condition is checked at the bottom of the loop. 

In the do while loop, the body of the loop will be executed first and then the condition will be evaluated. 

This ensures that the statement is executed at least once even if the condition is not satisfied.

It is an exit controlled loop.

Example:

#include 

using namespace std; 

int main() 

{ 

    int a = 1 ; 

    do

    { 

            cout << " The value of a is: " << a << endl; 

            a++; 

     } while ( a <= 5 ) ;

} 

Output:

The value of a is: 1

The value of a is: 2

The value of a is: 3

The value of a is: 4

The value of a is: 5