Question

public static int multiply2(int num1, int num2) {
    if (num1 == 0 || num2 == 0) {
        return 0;
    }

    else {
        return num1 + multiply2(num1, num2 - 1);
    }

}

I just realized that it would be fun to make a program that could determine the product of two numbers, one or both being negative. I want to do it using recursive multiplication (basically repeated addition). Could some one help me out? Thanks!

Answer 1

if (num1 == 0 || num2 == 0) {
        return 0;
}

else if( num2 < 0 ) {
    return - num1 + multiply2(num1, num2 + 1);
}

else {
    return num1 + multiply2(num1, num2 - 1);
}