Loop issue

Question

Ok, i've been trying since like 2 days ago to solve this problem, but i havent been able to do so.
this is the error i get:
what is your name: neo
Hello neo Do you want to go first? (1)Yes, (2)No
1
the number of marbles is: 42
How many marbles you want to remove? 60
the number of marbles left is -18
It is now the computer's turn
Exception in thread "main" java.lang.IllegalArgumentException: n must be positiv
e
        at java.util.Random.nextInt(Random.java:248)
        at GameTester.main(GameTester.java:61)
Press any key to continue...As you can see the game ends when i enter a number higher than the number of marbles. however, i dont want the game to end, i want it ask the question again, until the user enters a number thats is not greater than the number of marbles, and that is not greater than the number of marbles divided by 2.
this is the code i have so far, i've tried making a boolean method but it always escape the program, i want it to repeat the question:
System.out.print("How many marbles you want to remove? ");this is the code i have so far:
import java.util.Random;
public class Game
     private String name;
     private String answer;
     private int numMarbles;
     private int marblesTaken;
     private int pcMarblesTaken;
     int goodData;
     public Game(String name)
          this.name = name;
     public String getName()
          return name;
     public boolean getGoodData()
          //if(marblesTaken >= numMarbles || marblesTaken < 1 || marblesTaken > (numMarbles/2))
          //return true;
          if((marblesTaken > 1) && (marblesTaken <= (numMarbles/2)))
               return true;
               return false;     
     public int getNum()
          return marblesTaken;
}thanks for the support

Answer 1

This is the code i have so far:
import java.util.Random;
public class Game
     private String name;
     private String answer;
     private int numMarbles;
     private int marblesTaken;
     private int pcMarblesTaken;
     int goodData;
     public Game(String name)
          this.name = name;
     public String getName()
          return name;
     public void takeMarbles(int marbles)
         marblesTaken = marbles;
     public void updateMarbleCount()
         numMarbles = numMarbles - marblesTaken;
     public boolean getGoodData()
          //if(marblesTaken >= numMarbles || marblesTaken < 1 || marblesTaken > (numMarbles/2))
          //return true;
          if((marblesTaken > 1) && (marblesTaken <= (numMarbles/2)))
          return true;
          return false;     
     public int getNum()
          return marblesTaken;
     public int getMarbles()
          return numMarbles;
import java.util.Random;
import java.util.Scanner;
public class GameTester
     public static void main (String [] args)
          Scanner input = new Scanner(System.in);
          String exit = "1";
          do
               System.out.print("what is your name: ");
               String name = input.next();
               Game howdy = new Game(name);          
               String aString = "1";
               do
                    System.out.println("Hello " + howdy.getName() + " Do you want to go first? (1)Yes, (2)No");
                    aString = input.next();
               while(!aString.equals("1") && !aString.equals("2"));
                    if(aString.equalsIgnoreCase("1"))
                         Random random = new Random();
                         int min = 10;
                         int max = 100;
                         int diff = max - min + 1;
                         int numMarbles = random.nextInt(diff) + min;
                         System.out.println("the number of marbles is: " + numMarbles);
                         while(numMarbles > 1)
                         do
                             System.out.print("How many marbles you want to remove? ");
                             howdy.takeMarbles(input.nextInt());
                              while(!howdy.getGoodData());
                              howdy.updateMarbleCount();
                              System.out.println("the number of marbles left is " + numMarbles);
                              System.out.println("It is now the computer's turn");
                              int pcMarblesTaken = random.nextInt(numMarbles/2)+1;
                              System.out.println("the computer has taken " + pcMarblesTaken + " marbles");
                              numMarbles = numMarbles - pcMarblesTaken;
                              System.out.println("the number of marbles left is: " + numMarbles);
                              if (numMarbles==1)
                                   System.out.println(howdy.getName()+ " You lose");
                                   break;
                              System.out.println("It is now your turn");               
                    else
                         Random random = new Random();
                         int min = 10;
                         int max = 100;
                         int diff = max - min + 1;
                         int numMarbles = random.nextInt(diff) + min;
                         System.out.println("the number of marbles is: " + numMarbles);
                         while(numMarbles > 1)
                              int pcMarblesTaken = random.nextInt(numMarbles/2)+1;
                              System.out.println("the computer has taken " + pcMarblesTaken + " marbles");
                              numMarbles = numMarbles - pcMarblesTaken;
                              System.out.println("the number of marbles left is: " + numMarbles);
                              System.out.println("It is now your turn");
                              do
                                  System.out.print("How many marbles you want to remove? ");
                                  howdy.takeMarbles(input.nextInt());
                              while(howdy.getGoodData());
                              howdy.updateMarbleCount();
                              System.out.println("the number of marbles left is " + numMarbles);
                              if (numMarbles==1)
                                   System.out.println(howdy.getName()+" You Win!!");
                                   break;
                              System.out.println("It is now the computer's turn");
          do
          System.out.print("Do you want to play again? (1)Yes, (2)No ");
          exit = input.next();          
          while(!exit.equals("1") && !exit.equals("2"));
          if(exit.equals("2"))
               System.out.println("Thanks for playing with us!");
               break;
          while(exit.equals("1"));
}     whats the third method?? what does it do?? why is the program ignoring my input??
Thanks for the help!