C++ GCD & LCM

#include<iostream>
using namespace std;
int main()
{
    int n, m, r , lcm, a, b;

    cout << "Enter Two Number : ";
    cin >> n >> m;
    cout << endl;

    if(n<m)
    {
        r = n;
        n = m;
        m = r;
    }

    a = n;
    b = m;

    while(m != 0)
    {
        r = n % m;
        n = m;
        m = r;
    }

    cout << "GCD is : " << n << endl;

    lcm = (a * b)/n;

    cout << "LCM is : " << lcm << endl;

    return 0;
}