C Program to Find G.C.D Using Recursion

Example to find the GCD of two positive integers (entered by the user) using recursion in C programming.

To understand this example, you should have the knowledge of following C programming topics:

This program takes two positive integers as input from the user and calculates GCD using recursion.

Visit this page to learn how you can calculate the GCD using loops.

Example: GCD of Two Numbers using Recursion

#include <stdio.h>
int hcf(int n1, int n2);
int main()
{
   int n1, n2;
   printf("Enter two positive integers: ");
   scanf("%d %d", &n1, &n2);

   printf("G.C.D of %d and %d is %d.", n1, n2, hcf(n1,n2));
   return 0;
}

int hcf(int n1, int n2)
{
    if (n2 != 0)
       return hcf(n2, n1%n2);
    else 
       return n1;
}

Output

Enter two positive integers: 366
60
G.C.D of 366 and 60 is 6.