#include <stdio.h>

int gcd(int a, int b);
int gcd_mod(int a, int b);
int gcd_rec(int a, int b);
int lcm(int a, int b);

int main() {
    int m, n, a, b;

    // Getting m and n from STDIN
    printf("Write m and n: ");
    scanf("%d %d", &m, &n);

    // Calculate the GCD using the gcd function
    int result = gcd(m, n);
    // Print the result
    printf("The Greatest Common Divisor (GCD) of m and n is \t%d (lecture)\n", result);

    // Calculate the GCD using the gcd function
    int result2 = gcd_mod(m, n);
    // Print the result
    printf("The Greatest Common Divisor (GCD) of m and n is \t%d (modulo)\n", result2);

    // Calculate the GCD using the gcd function
    int result3 = gcd_rec(m, n);
    // Print the result
    printf("The Greatest Common Divisor (GCD) of m and n is \t%d (recursion)\n", result3);

    // Calculate the LCM using the gcd function
    // e.g. lcm(4,6)=12
    int result4 = lcm(m, n);
    // Print the result
    printf("The Least Common Multiple (LCM) of m and n is \t%d\n", result4);
    return 0;
}

int gcd(int a, int b) {
    /* GCD(a, b) - Lecture notes (substraction version) */

    while (a != b) {
        if (a < b) {
            b = b - a;
        } else {
            a = a - b;
        }
    }
    return a;
}

int gcd_mod(int a, int b) {
    /* GCD(a, b) - Modulo version */
    while (b != 0) {
        int t = b;
        b = a % b;
        a = t;
    }
    return a;
}

int gcd_rec(int a, int b) {
    /* GCD(a, b) - recursion version */
    if (b == 0) {
        return a;
    } else {
        return gcd_rec(b, a % b);
    }
}

int lcm(int a, int b) {
    /*
     Calculate Least Common Multiple (LCM) using GCD
     LCM * GCD = m * n
    */
    return (a * b) / gcd_mod(a, b);
}