C Program to find GCD of two numbers using recursion

In this tutorial, we will learn the writing program in C to find the GCD of two numbers using recursion. In the previous tutorial, we have learnt to write the c program to calculate GCD without recursion.

Program in C to find GCD using recursion

#include <stdio.h>
int gcd(int num1, int num2)
{
    if (num2 == 0)
        return num1;
    return gcd(num2, num1 % num2);
}
 
int main()
{
    int num1, num2, maxNum;
    printf("Find GCD or HCF of two numbers using recursion\n");
    printf("Enter the first number: ");
    scanf("%d", &num1);
    printf("Enter the second number: ");
    scanf("%d", &num2);
    printf("GCD or HCF of numbers %d and %d is %d ", num1, num2, gcd(num1, num2));
    return 0;
}

Output 1

Find GCD or HCF of two numbers using recursion
Enter the first number: 23
Enter the second number: 55
GCD or HCF of numbers 23 and 55 is 1 

Output 2

Find GCD or HCF of two numbers using recursion
Enter the first number: 12
Enter the second number: 20
GCD or HCF of numbers 12 and 20 is 4 

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