Write a program to find GCD or HCF of two numbers. In this tutorial, we are going to write following programs.

In this example, our program will take two input integer and then compute it's GCD or HCF using recursion. If you don't know about recursion then read this awesome post on recursion vs iteration.

GCD or HCF of two numbers is the largest number which divides both the number without leaving any remainder.

Binary Search program in C, C++

Let's take an

Take two numbers 63 and 21.

Divisible of 63 is 3, 7, 9, 21 ,63

Divisible of 21 is 3, 7, 21

Highest Divisible of both the numbers without leaving any remainder is 21.

Check whether number is Armstrong or not

Enter two numbers : 15 25

GCD of two numbers is : 5

- Write a C program to find GCD or HCF of two numbers.
- Write a C++ program to find GCD or HCF of two numbers.

In this example, our program will take two input integer and then compute it's GCD or HCF using recursion. If you don't know about recursion then read this awesome post on recursion vs iteration.

### What is GCD (Greatest Common Divisior) or HCF (Highest Common Factor) ?

GCD or HCF of two numbers is the largest number which divides both the number without leaving any remainder.

Binary Search program in C, C++

Let's take an

**example**-Take two numbers 63 and 21.

Divisible of 63 is 3, 7, 9, 21 ,63

Divisible of 21 is 3, 7, 21

Highest Divisible of both the numbers without leaving any remainder is 21.

Check whether number is Armstrong or not

## C++ Program to Find GCD of Two Numbers using Recurison

#include <iostream> using namespace std; int gcd(int a, int b) { // If b is zero if(b == 0){ return a; } return gcd(b, a%b); } int main() { int num1, num2, result; cout << "Enter two numbers \n"; cin >> num1 >> num2; result = gcd(num1, num2); cout << "GCD of two numbers is " << result; return 0; }

## C Program to Find GCD of Two Numbers using Recursion

#include <stdio.h> int gcd (int a, int b) { /* If b is equal to zero. */ if(b == 0) { return a; } // Recursive call gcd(b, a%b); } int main(void) { int a, b, g; printf("Enter two numbers \n"); scanf("%d %d",&a, &b); g = gcd(a, b); printf("GCD of two numbers %d %d is %d",a,b,g); return 0; }

**Output :**

Enter two numbers : 15 25

GCD of two numbers is : 5