Nested Loops in C

In this article, you will come to know about the nested loops in C programming and the usage of it.

Nested Loops in C

Nesting of loops is a key feature in C, which allows the looping of statements inside another loop. N number of loops can be defined inside another loop, i.e., there is no restriction for defining the number of loops.

A nested loop is a loop statement inside another loop statement. Hence nested loops are also called “loop inside loop’’.

You can also define any type of loop inside another loop; for example, you can define a do….while loop inside for loop. You can use one or more loops inside any other while, for, or do….while loop.

Syntax for Nested For loop

for( initialization; condition; increment ) 
{
  for ( initialization; condition; increment ) 
  {
  // statements of inside loop
  }
  // statements of outer loop
}

Syntax for Nested While loop

while(condition) {
  while(condition) {
  // statements of inside loop
  }
  // statements of outer loop
}

Syntax for Nested Do-While loop

do
{
  do{
  // statements of inside loop
}while(condition);
  // statements of outer loop
}while(condition);

Below, let us look at an example of a nested for loop.

Example

#include <stdio.h>
int main()
{
    for (int i=0; i<2; i++)
    {
    for (int j=0; j<3; j++)
    {
        printf("%d, %d\n",i ,j);
    }
    }
    return 0;
}

Output

0, 0
0, 1
0, 2
1, 0
1, 1
1, 2

As the above example, the other loops like while, do..while can also be nested the same way.