how to find gcd of two numbers in cpp code example

Example 1: gcd function in c++

int gcd(int a, int b) 
{ 
    // Everything divides 0  
    if (a == 0) 
       return b; 
    if (b == 0) 
       return a; 
    // base case 
    if (a == b) 
        return a; 
    // a is greater 
    if (a > b) 
        return gcd(a-b, b); 
    return gcd(a, b-a); 
}

Example 2: c++ program to find gcd of 3 numbers

#include<stdio.h>
int main() {    
  int a,b,c,hcf,st;
  printf("Enter three numbers : ");
  scanf("%d,%d,%d", &a,&b,&c);
  st=a<b?(a<c?a:c):(b<c?b:c);
  for (hcf=st;hcf>=1;hcf--) 	{  	  
    if (a%hcf==0 && b%hcf==0 && c%hcf==0)
      break;
  }
  printf("%d",hcf); return 0;
}