Question

Design a class that can be used to simulate rolling a multi-faced die.

2. Write a Java class called Die in a class file called Die.java.   

3. The Die class will have three private class attributes: a. The first attribute, called numSides, is of type int and represents the number of sides on the die.

b. The second attribute, called sumRolls, is static of type int and will keep track of the sum of multiple die rolls by multiple dice.

c. The third attribute, called r is of type Random and is used to generate random integer values within your program.   

4. The Die class contains a constructor, three non-static methods, and one static method:
a. The constructor takes one argument, called sides, of type int. The constructor should initialize the numSides attribute. If sides is less than 2 or larger than 100, then numSides should be set to a default value of six (6). Otherwise, numSides should be set to the value of sides. Also, the constructor should instantiate a new Random object and assign it to attribute r.

b. The public method called getNumSides() is an accessor for the numSides attribute.

c. The public method called setNumSides() is an mutator for the numSides attribute. It should have a single parameter called sides of type int.

d. A public method called getRollSum() that is also static and is an accessor for the sumRolls attribute.

e. A public method called rollDie() that generates and return a random integer value between one (1) and the value of numSides.

5. You will need to write a separate class containing a main method to test your code. The example below is provided along with the expected output to assist you. The provided example does NOT sufficiently test the Die class (but, it is a start).

public class TestDie { public static void main(String[] args) { Die d1 = new Die(6); Die d2 = new Die(10); System.out.println("Die 1 has " + d1.getNumSides() + " sides."); System.out.println("Die 2 has " + d2.getNumSides() + " sides."); d1.setNumSides(10); System.out.print("Die 1 now has "); System.out.println(d1.getNumSides() + " sides."); System.out.println("Roll on Die 1: " + d1.rollDie()); System.out.println("Roll on Die 2: " + d2.rollDie()); System.out.print("The sum of the two rolls: "); System.out.println(Die.getRollSum()); } }


Assuming that your Die class is correct, the above code should produce the following result (Hint: the values of the rolls and sum will vary for each run):

Die 1 has 6 sides. Die 2 has 10 sides. Die 1 now has 10 sides. Roll on Die 1: 9 Roll on Die 2: 8 The sum of the two rolls: 17

Answer 1

// Screenshot of the code & output

// code to copy

Die.java

import java.util.Random;
public class Die {
   int numSides;
   static int sumRolls;
   Random r;
   // constructor
   public Die(int sides) {
       if(sides<2 || sides>100) {
           this.numSides=6;
       }else {
           this.numSides=sides;
       }
   this.r=new Random();     
   }
   public int getNumSides() {      
       return numSides;
   }
   public void setNumSides(int i) {
       this.numSides=i;      
   }
   public static int getRollSum() {      
       return sumRolls;
   }

   public int rollDie() {  
       int rolls= (int) (Math.random() * numSides) + 1;
       sumRolls+=rolls;
       return rolls;
   }
  
}

TestDie.java

public class TestDie {

   public static void main(String[] args) {
       Die d1 = new Die(6);
       Die d2 = new Die(10);
       System.out.println("Die 1 has " + d1.getNumSides() + " sides.");
       System.out.println("Die 2 has " + d2.getNumSides() + " sides.");
       d1.setNumSides(10); System.out.print("Die 1 now has ");
       System.out.println(d1.getNumSides() + " sides.");
       System.out.println("Roll on Die 1: " + d1.rollDie());
       System.out.println("Roll on Die 2: " + d2.rollDie());
       System.out.print("The sum of the two rolls: ");
       System.out.println(Die.getRollSum());

   }

}