// Using only if, else, while, and add(x, y), write 3 functions to implement *, -, / operation.
// You are not allowed to use the operator of * - /, and you are provided with the add function, 
// NEGATIVE_ONE -1 value and ONE holding 1 value.

const NEGATIVE_ONE = -1;
const ONE = 1;

function add(a, b) {
    return a + b
}

function multiply(a, b) {
    let result = a;
    for (let i = 1; i < b; i++) {
        result = add(result, a);
    }

    return result;
}

function minus(a, b) {
    let result = a
    for (let i = 0; i < b; i++) {
        result = add(result, NEGATIVE_ONE);
    }

    return result;
}

function divide(a, b) {
    let counter = 0;
    if (a === 0) {
        return 0;
    }

    if (b === 0) {
        return 'Not a number'
    }

    if ((a % b) === 0) {
        let counter = 0;
        while (a > 0) {
            for (let i = 0; i < b; i++) {
                a = add(a, NEGATIVE_ONE);
            }
            counter = add(counter, ONE);
        }
        return counter;
    } else {
        return 'error';
    }
}

console.log(minus(6, 78) , ' :answer is -72'); // -72
console.log(minus(94, 17) , ' :answer is 77'); // 77
console.log(minus(10, 5) , ' :answer is 5'); // 5
console.log(multiply(7, 3), ' :answer is 21'); // 21
console.log(divide(14, 7), ' :answer is 2'); // 2
console.log(divide(36, 9), ' :answer is 4'); // 4
console.log(divide(48, 4), ' :answer is 12'); // 12
console.log(divide(15, 7), ' :answer is error'); // error