Thread: do while loop with nested while question

okay thanks for the help copeg. if anyone is familiar with netBeans can u tell me why it keeps running until i press enter then on the blank line put in any number and press enter then it stops running and says build successful. There are no syntax errors.

/*This program prompts the user for a number 1-20 and compares it with a
 * randomly generated number. If it matches the program displays you won.
 * if not, it displays try again. The program also displays the number of
 * guesses. It also does not count invalid entries as guesses no matter where in
 *  the program they are entered.
 */
import java.util.Scanner;
import java.util.Random;
/**
 *
 * @author John LaFave
 */
public class labAssign5 {
 
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        Scanner keyboard = new Scanner(System.in);
        int rNumber, userGuess;
        int totalGuesses;
        Random rGenerate = new Random();
        rNumber = rGenerate.nextInt(20) + 1;
        totalGuesses = 0;
 
 
 
 
        do
        {
            System.out.print("Enter a number 1 to 20 -> ");
            userGuess = keyboard.nextInt();
 
            {
                while (userGuess <=20 && userGuess >=1 && userGuess != rNumber)
                {
                    System.out.print("Try again.\nEnter a number"
                + " 1 to 20 -> "); userGuess = keyboard.nextInt();
 
                        totalGuesses ++;
                }
 
 
                        if (userGuess == rNumber)
                    {
                       totalGuesses ++;
                     System.out.print("You won!\nThe number of guesses is "
                     + totalGuesses);
                     userGuess = keyboard.nextInt();
 
                    }
 
 
            }
 
        } while (userGuess < 1 || userGuess > 20);
 
       System.exit(0);
   } }

Likely it's a problem with your timing and what order you're doing stuff in. Save your work, then close netbeans. This will effectively terminate any programs NetBeans could be running/building. Then re-start netbeans. Click the build button once. Be patient, it may take a while for it to finish building. Once it tells you that it's finished building, click the Run button once. Again, it may take a while for the program to start up. Also, once you're done, make sure your program has terminated (or forcibly terminate it). This will prevent any weird things from happening such as accidentally inputting data to the old program.

okay I figured out that my outer do-while loop wants to keep running when I want the program to end after my nested while loop gets the random number match. I can terimnate the program by entering an int into the console that makes the do-while false but that doesn't really work for an efficient program. I tried using break but it either stops the whole thing or does notjing depending on placement. Any thoughts would be awesome.oh and I tried nesting the do-while inside the while but couldn't get it to work. does anyone think thats the way to go or the force stop?

You had a put System.in during your if loop, not sure why. Try this

/*This program prompts the user for a number 1-20 and compares it with a
 * randomly generated number. If it matches the program displays you won.
 * if not, it displays try again. The program also displays the number of
 * guesses. It also does not count invalid entries as guesses no matter where in
 *  the program they are entered.
 */
import java.util.Scanner;
import java.util.Random;
/**
 *
 * @author John LaFave
 */
public class labAssign5 {
 
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        Scanner keyboard = new Scanner(System.in);
        int rNumber, userGuess;
        int totalGuesses;
        Random rGenerate = new Random();
        rNumber = rGenerate.nextInt(20) + 1;
        totalGuesses = 0;
 
 
 
 
        do
        {
            System.out.print("Enter a number 1 to 20 -> ");
            userGuess = keyboard.nextInt();
 
            {
                while (userGuess <=20 && userGuess >=1 && userGuess != rNumber)
                {
                    System.out.print("Try again.\n" + 
                   "Enter a number 1 to 20 -> ");  userGuess = keyboard.nextInt();
 
                        totalGuesses ++;
                }
 
 
                        if (userGuess == rNumber)
                    {
                       totalGuesses ++;
                     System.out.print("You won!\nThe number of guesses is " + totalGuesses);
                     System.out.println("["+userGuess+"]" + "["+rNumber+"]");
 
                    }
 
 
            }
 
        } while (userGuess < 1 || userGuess > 20);
 
       System.exit(0);
   } }

The point of

 System.out.println("["+userGuess+"]" + "["+rNumber+"]");

is to test if those are even, if they are and it still doesn't end the while statement than I have no clue.
It will look funny, but if it ends like it should, just delete that line. I added my own style, you can change it if you want, shouldn't make a difference.
Also for testing purposes you could add rNumber = 1 and see if it ends like it should without guessing the number.