**What is GCD of two numbers?**

It means a greatest number which divides both numbers

**For example:** Two numbers are 18 and 24

Numbers which divides both are 1, 2, 3 and 6 in which greatest number is 6

So 6 is the GCD of 18 and 24

### C++ Program

#include<iostream> using namespace std; int main() { int first_number; cout<<"Enter First Number : "; cin>>first_number; int second_number; cout<<"Enter Second Number: "; cin>>second_number; int gcd; for (int i=1;i<=first_number&&i<=second_number;i++) { if(first_number%i==0 && second_number%i == 0 ) { gcd=i; } } cout<<"Greatest Common Divison (GCD):"<<gcd<<endl; return 0; }