GCD/HCF and LCM

 Euclidean Theorm: gcd (a, b) = gcd (b, a % b)

HCF * LCM = a * b

public class GCD_LCM {
    public static void main(String[] args) {
        int a = 36;
        int b = 24;

        int original_a = a, original_b = b;
        while (b > 0) {
            int rem = a % b;
            a = b;
            b = rem;
        }

        System.out.println("HCF: " + a);

        System.out.println("LCM: " + original_a * original_b / a);


    }
}