Least common multiple calculator via greatest common denominator using Euclid's method. Includes both iterative and recursive implementations.

LCM.c

int gcdIterative(int a, int b) {
    while(true) {
        if(a > b) {
            a -= b;
            continue;
        }
        if(b > a) {
            b -= a;
            continue;
        }
        // if a == b
        return a;
    }
}

int gcdRecursive(int a, int b) {
    if(a > b) {
        return gcdRecursive(a - b, b);
    }
    if(b > a) {
        return gcdRecursive(a, b - a);
    }
    // if a == b
    return a;
}

// LCM (a, b) = a / GCD(a, b) * b
int lcm(int a, int b) {
    return a / gcdIterative(a, b) * b;
}