Myujth

I'm writing a dice game program that creates a die for the user and computer, then asks for user name, number of sides on dice, and how many iterations the user would like to play with the computer. Then have the program check after each roll to see which roll is higher and at the end of the iterations it writes back the total wins for each user and computer and who the winner is. The problem i'm having is that I need to create a roll() class to randomize the dice and set it to a value for the users roll and computers roll and i'm getting this error...

Exception in thread "main" java.lang.IllegalArgumentException: bound must be positive
at java.util.Random.nextInt(Random.java:388)
at classwork6_3.Die.roll(Die.java:52)
at classwork6_3.ClassWork6_3.main(ClassWork6_3.java:29)

Here is my main() class...

package classwork6_3;
import java.util.*;

public class ClassWork6_3 

public static void main(String args) 

 Scanner s = new Scanner(System.in);
 Random r = new Random();

 System.out.print("Enter user's name: ");
 String name = s.nextLine();
 int value = 0;
 int value2 = 0;
 System.out.print("How many sides does the die have?: ");
 int sides = s.nextInt();
 s.nextLine();
 System.out.print("How many times would you like to roll?: ");
 int numRoll = s.nextInt();
 int counter = 0;
 int counter2 = 0;

 Die user = new Die(name, sides, value);
 Die comp = new Die(value);

 for(int i = 1; i<= numRoll; i++)

 value = r.nextInt(user.roll(sides)) + 1;
 value2 = r.nextInt(comp.roll(sides)) + 1;

 System.out.printf("%s rolled: %dn", user.getOwner(), user.getValue());
 System.out.print("Computer rolled: " + comp.getValue() + "nn");

 if(value > value2)
 counter++;
 else if(value2 > value)
 counter2++;
 

 
 System.out.printf("%s TOTAL WINS: %dn", user.getOwner(), counter);
 System.out.print("Computer TOTAL WINS: " + counter2 + "nn");
 if(counter > counter2)

 System.out.printf("%s wins!!n", user.getOwner());
 else if(counter2 > counter)

 System.out.print("Computer winsn");
 else

 System.out.print("It's a tie!n");
 

Here is my Die() class...

package classwork6_3;
import java.util.*;


public class Die 

Random r = new Random();

private int sides;
private int value;
private String owner;


public Die(String owner, int sides, int value)

 this.sides = sides;
 this.value = value;
 this.owner = owner;

public Die (int value)

 this.value = value;


public int getSides()

 return sides;

public int getValue()

 return value;

public String getOwner()

 return owner;

public void setSides(int sides)

 this.sides = sides;

public void setValue(int value)

 this.value = value;

public void setOwner(String owner)

 this.owner = owner;

public int roll(int rand)

 rand = r.nextInt(value);

 return value;

Here are the issues with your code :

1. 
   

   You are never returning the random value generated by the roll(...) method

   
   
   

   public int roll(int rand)
    rand = r.nextInt(value); 
    return value;
   
   

   
   
   

   Change it to

   
   
   

   public int roll(int rand) 
    return r.nextInt(rand); 
   
   

   
   


2. 
   

   Within the for-loop all you need to do is just call the roll()
   method. Since it already calculates the random value of the die, there is no need for you to call r.nextInt() again.

   
   
   

   value = r.nextInt(user.roll(sides)) + 1;
   value2 = r.nextInt(comp.roll(sides)) + 1;
   

   
   
   

   Change it to

   
   
   

   value = user.roll(sides) + 1;
   value2 = comp.roll(sides) + 1;
   

   
   


3. 
   

   Now print out the values using :

   
   
   

   System.out.printf("%s rolled: %dn", user.getOwner(), value);
   System.out.print("Computer rolled: " + value2 + "nn");
   

   
   

Your code will work as expected after performing the above mentioned steps. Also as a side note do not use variable names that have an ambiguous meaning like value, value2 etc.

Whenever you make a new die, your value is never changed from zero, causing that error to pop-up since the range it would be looking through whenever you call roll(), acording to your Die class, is 0 to 0. Change value to the value the user puts in and the make a new die.