package com.company;

public class Main {
    //Default function
    static final int NEGATIVE_ONE = -1;
    static final int ONE = 1;

    static int add(int firstValue, int secondValue) {
        return firstValue + secondValue;
    }

    static int negate(int a) {
        int c;
        int n = 0;
        if (a > 0) {
            c = NEGATIVE_ONE;
        } else {
            c = ONE;
        }
        while (a != 0) {
            a = add(a, c);
            n = add(n, c);
        }
        return n;
    }
    //////////////////////////////////////////////////////////////////////
    //Pseudocode is the comment of gist.
    static int minus(int firstVal, int secondVal) {
        return firstVal + negate(secondVal);
    }

    static int multiply(int firstVal, int secondVal) {
        int answer = 0;
        for (int i = 0; i < secondVal; i++) {
            answer += firstVal;
        }
        return answer;
    }

    static int divide(int firstVal, int secondVal) {
        if (secondVal == 0) {
            throw new ArithmeticException("Cannot divide by zero!");
        }
        int count = 0;
        int tmp = firstVal;
        while (tmp > 0) {
            tmp -= secondVal;
            count++;
            if (tmp == 0)
                break;
            if (tmp < 0) {
                System.out.println("error");
                return -1;
            }
        }
        return count;
    }

    public static void main(String[] args) {
        System.out.println(minus(10, 5));
        System.out.println(multiply(7, 3));
        System.out.println(divide(14, 7));
        System.out.println(divide(15, 7));   //-1 to indicate error
    }
}