Write a C, C++ program to find GCD of two numbers. In this program, our program will take two input integer and then compute it's GCD or HCF.

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

Binary Search Algorithm

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

### 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 Algorithm

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