Passing random numbers into an instance of an object

Question

my homework is asking me to do a math game in which I prompt the user to answer math questions and then show them the answer. I've created the MathGameclass, but when I create an instance of MathGame, it asks me to put in two ints, which I don't know because I'm trying to generate them randomly.

Question: How do I get my random numbers from the class to pass into the instance of MathGame?

Below is the MathGame class

Underneath that is the main with the instance of MathGame I'm trying to figure out.

import java.util.Random;

public class MathGame {

    private int operand1;
    private int operand2;
    private int solution;

    public MathGame(int operand1, int operand2) {
        this.operand1 = operand1;
        this.operand2 = operand2;
    }

    public int genRandom1() {
        Random rand = new Random();
        int randNum = rand.nextInt(0) + 20;
        randNum = operand1;
        return operand1;
    }

    public int genRandom2() {
        Random rand = new Random();
        int randNum2 = rand.nextInt(0) + 20;
        randNum2 = operand2;
        return operand2;
    }

    public int getoperand1() {
        return operand1;
    }

    public int getoperand2() {
        return operand2;
    }

    public String question() {
        return "What is" + operand1 + operand2 + "?";
    }

    public String solution() {
        int solution = operand1 + operand2;
        return "The correct answer is: " + solution;
    }

}

I get an error in the instance of MathGame since I need to have two ints go through, but I don't know the ints obviously because they're supposed to be randomly generated, which I did in the class.

import java.util.Scanner;

public class MathGameMain {

    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        MathGame game1 = new MathGame();
    }

}

Answer 1

this is what i got from your comment,

1. call the MathGame object on Main class, and the constructor of MathGame returned 2 random number that stored on operand1 and operand2

2. the program will resulting a number by adding operand1 to operand2

Solution

import java.util.Random;

public class MathGame {

    private int operand1;
    private int operand2;
    private int solution;

    public MathGame ()
    {
        this.operand1 = genRandom();
        this.operand2 = genRandom();
    }

    public int genRandom()
    {
        Random rand = new Random();

        int randNum = rand.nextInt(0) + 20;

        return randNum;
    }

    public String question()
    {
        return "What is" + this.operand1 + " + " + this.operand2 + "?";
    }

    public String solution()
    {
        int solution = operand1 + operand2;

        return "The correct answer is: " + solution;
    }

}

in main class

import java.util.Scanner;


public class MathGameMain {

    public static void main(String[] args) {
        MathGame game1 = new MathGame();

        //question
        System.out.println(game1.question());

        // solution
        System.out.println(game1.solution());
    }

}

Answer 2

what do you want in this method

public int genRandom1()
{
    Random rand = new Random();
    int randNum = rand.nextInt(0) + 20;
    randNum = operand1;
    return operand1;
}

and

public int genRandom2()
{
    Random rand = new Random();
    int randNum2 = rand.nextInt(0) + 20;
    randNum2 = operand2;
    return operand2;
}

you create a process and stored it to randNum but what you returned in the method was operand2. just return the randNum instead.

Answer 3

You probably want to change to something like this:

import java.util.Random;                                                     


public class MathGame {                                                      

  private int operand1;                                                      
  private int operand2;                                                      
  private int solution;                                                      

  public MathGame ()                                                         
  {                                                                          
    this.operand1 = getRandom();                                             
    this.operand2 = getRandom();                                             
  }                                                                          

  public int getRandom()                                                     
  {                                                                          
    Random rand = new Random();                                              
    int randNum = rand.nextInt(20);                                          
    return randNum;                                                          
  }                                                                          

  public int getoperand1()                                                   
  {                                                                          
    return operand1;                                                         
  }                                                                          

  public int getoperand2()                                                   
  {                                                                          
    return operand2;                                                         
  }                                                                          

  public String question()                                                   
  {                                                                          
    return "What is" + operand1 + " + " + operand2 + "?";                    
  }                                                                          

  public String solution()                                                   
  {                                                                          
    int solution = operand1 + operand2;                                      
    return "The correct answer is: " + solution;                             
  }                                                                          

}      

You should generate the random numbers when the MathGame is initialized. No need to pass numbers if you are going to randomly generate them.