C++ Do-While Loop - Learn With AVRK

Do-While Loop in C++ Language

Do-While loop is used to repeat a part of the program multiple times. If the number of repetitions are not fixed and you have to execute the loop at least once, Then it is suggested to use a do-while loop instead of while loop.

The do-while loop is executed at least once because the condition is checked at the end of the loop body.

do
{
 /*code to be executed */  
}
while(condition);  

Flowchart -

Do-while Loop Example -

Let's look at an example using a do-while loop to print a table of 1.

#include<iostream> 
using namespace std;  
int main() {  
     int i = 1;    
          do{    
              cout<<i<<"\n";  
              i++;    
          } while (i <= 10) ; 
}  

Output -

1
2
3
4
5
6
7
8
9
10

Nested do-while Loop

If you use a do-while loop inside another do-while loop, it is known as a nested do-while loop. For each outer do-while loop the inner do-while loop executes completely.

Let's look at an example using nested do-while loops -

#include<iostream> 
using namespace std;  
int main() {  
     int i = 1; 
do{
              int j = 1;   
          do{    
                cout<<i<<j<<" "; 
              j++;    
          } while (j <= 3) ; 
cout<<endl;  
              i++;  
          } while (i <= 3) ;  
 cout<<endl; 
}  

Output -

11 12 13
21 22 23
31 32 33

Infinite do-while Loop

If you passes always true value in a do-while loop, it will be an infinite do-while loop.

do
{
 /*code to be executed */  
}
while(true);  

Infinite do-while Loop Example -

Let's look at an example using infinite do-while loops.

#include <iostream> 
using namespace std;  
int main() {  
int i = 1; 
do{
cout<<"Infinite do-while Loop";
} while (true) ;  
}  

Output -

Infinite do-while Loop
Infinite do-while Loop
Infinite do-while Loop
Infinite do-while Loop
Infinite do-while Loop
Ctrl + C

Also check this out : C++ While loop - Learn With AVRK