GCD and LCM

GCD (Greatest Common Divisor) and LCM (Least Common Multiple) are two important concepts in mathematics. They are used to find the greatest common factor or the smallest multiple of two or more numbers.

#include <iostream>
using namespace std;

int gcd(int a, int b) {
    while(b != 0){ // a, b = b, a % b
        int temp = b; 
        b = a % b;
        a = temp;
    }
    return a;
}

int lcm(int a, int b) {
    return (a * b) / gcd(a, b);
}

int main() {
    int a, b;
    cout << "Enter two numbers: ";
    cin >> a >> b;
    cout << "GCD of " << a << " and " << b << " is " << gcd(a, b) << endl;
    cout << "LCM of " << a << " and " << b << " is " << lcm(a, b) << endl;
    return 0;
}

In the above code, the gcd function uses the Euclidean algorithm to find the greatest common divisor of two numbers. The lcm function first finds the GCD of the two numbers and then multiplies them to find the LCM.