import java.util.Scanner;

import java.util.Random;

public class AlgebraTutor {

    static Random random = new Random();

    static int m = -100 + random.nextInt(201);
    static int x = -100 + random.nextInt(201);
    static int b = -100 + random.nextInt(201);
    static int y = -100 + random.nextInt(201);

    static int correct_answer_y = (m * x) + b;
    static int correct_answer_m = (y - b) / x;
    static int correct_answer_b = (y - (m * x));

    static Scanner input = new Scanner(System.in);

    static Scanner selection = new Scanner(System.in);

    static int user_selection = 0;

    public static void main(String[] args) {
    while (user_selection != 4) {
    prompt();
    }
    }

    public static void prompt() {

    System.out.println("If you would like to solve for y, please enter 1.");
    System.out.println("If you would like to solve for m, please enter 2.");
    System.out.println("If you would like to solve for b, please enter 3.");
    System.out.println("If you would like to quit, please enter 4.");
    int user_selection = input.nextInt();

    while ((user_selection != 1) && (user_selection != 2) && (user_selection != 3) && (user_selection != 4)) {
    user_selection = input.nextInt();
    }

    if (user_selection == 1) {
    solveForY();
    }

    if (user_selection == 2) {
    solveForM();
    }

    if (user_selection == 3) {
    solveForB();
    }

    if (user_selection == 4) {
    System.exit(0);

    }


    }

    public static boolean solveForY() {

    System.out.println("Given: \n");
    System.out.println("m = " + m);
    System.out.println("x = " + x);
    System.out.println("b = " + b);
    System.out.println();
    System.out.print("What is the value of y? ");

    int user_answer = input.nextInt();

    if (user_answer != correct_answer_y) {
        System.out.println("Sorry, that's wrong. The answer is " + correct_answer_y);
                           }

    else {
        System.out.println("Correct!");
                           }
    return (user_answer != correct_answer_y);
    }
    public static boolean solveForM() {

    System.out.println("Given: \n");
    System.out.println("y = " + y);
    System.out.println("x = " + x);
    System.out.println("b = " + b);
    System.out.println();
    System.out.print("What is the value of m? ");

    int user_answer = input.nextInt();

    if (user_answer != correct_answer_m) {
        System.out.println("Sorry, that's wrong. The answer is " + correct_answer_m + ".");
    }

    else {
        System.out.println("Correct!");
    }
    return (user_answer != correct_answer_m);

    }

    public static boolean solveForB() {

    System.out.println("Given: \n");
    System.out.println("y = " + y);
    System.out.println("x = " + x);
    System.out.println("m = " + m);
    System.out.println();
    System.out.print("What is the value of b? ");

    int user_answer = input.nextInt();

    if (user_answer != correct_answer_b) {
        System.out.println("Sorry, that's wrong. The answer is " + correct_answer_b + ".");
    }

    else {
        System.out.println("Correct!");
    }
    return (user_answer != correct_answer_b);

    }

}