C Program to Find GCD or HCF of Two Numbers using For Loop

In this C program, we will find GCD (Greatest Common Divisor) of two numbers using for loop. The highest common factor (HCF) of two or more integers, is the largest positive integer that divides the numbers without a remainder.
HCF is also known as greatest common divisor (GCD) or greatest common factor(GCF)

Required Knowledge

Algorithm to find GCD of two numbers
Let, A and B are two numbers.
  • Find minimum of A and B. Let A < B.
  • Find the largest number between 1 to A, which divides A and B both completely.

C program to find gcd of two numbers using for loop

#include <stdio.h>  

int getMinimum(int a, int b){
    if(a >= b)
        return b;
        return a;

int main() {  
    int a, b, min, counter, gcd = 1;  
    printf("Enter two numbers\n");  
    scanf("%d %d", &a, &b);  
    min = getMinimum(a, b);
    for(counter = 1; counter <= min; counter++) {  
        if(a%counter==0 && b%counter==0) {
            /* Update GCD to new larger value */ 
            gcd = counter;  
    printf("GCD of %d and %d = %d\n", a, b, gcd);
    return 0;  
Enter two numbers
15 50
GCD of 15 and 50 = 5
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