Problem

Generate a program where the computer chooses a random number between 1 and 10 and the user is continuously asked to guess it until they are correct. Use the following guidelines in coming up with a solution:

• [JOptionPane for input and ouput]
• Math.random() for generating the random number
• While loop for continuously asking for a guess until right
• Boolean variable for indicating when the while loop is done

While and For Loops

Solution

To use Math.random() and JOptionPane you will need to include the following import statements.

import java.lang.Math; //needed for Math.random
import javax.swing.JOptionPane; //needed for JOptionPane

We are also going to need 3 variables; int randNum, String guess, boolean correct.

int randNum; //used to store the randNum we generate
String guess; //used to store the guess
boolean correct = false; //loop variable initialized to false meaning our guess is incorrect

To generate a random number between 1 and 10 we will need to use the following code.

//(int)(Math.random() * 10 generates a random number from 0 to 9
//to get a random number from 1 to 10 we need to add 1
randNum = (int)(Math.random() * 10) + 1;

Code

Solution Code

import java.lang.Math; //needed for Math.random
import javax.swing.JOptionPane; //needed for JOptionPane

public class GuessMyNumber
{
    public static void main(String [ ] args)
    {
        int randNum = (int)(Math.random() * 10) + 1;
        String guess;
        boolean correct = false;
        
        while(correct == false)
        {
            guess = JOptionPane.showInputDialog("Enter a guess between 1 and 10:");
            if(guess != null)
            {
                if(Integer.parseInt(guess) == randNum)
                {
                    correct = true;
                    JOptionPane.showMessageDialog(null, "You are correct", "", JOptionPane.INFORMATION_MESSAGE);
                }
                else
                    JOptionPane.showMessageDialog(null, "You are incorrect", "", JOptionPane.INFORMATION_MESSAGE);
            }
        }
    }
}