USER-DEFINED CLASSES AND ADTS - Java Programming: From Problem Analysis to Program Design - page 499

//Method to roll a die.
//This method uses a random number generator to randomly
//generate a number between 1 and 6, and stores the number
//in the instance variable num and returns the number.
public int roll()
{

num = ( int ) (Math.random() * 6) + 1;

return num;

}

//Method to return the number on the top face of the die.
//Returns the value of the instance variable num.
public int getNum()
{

return num;

}

//Returns the value of the instance variable num as a string.
public String toString()
{

return "" + num;

}

}
We leave the UML class diagram of the class RollDie as an exercise for you.
The following program shows how to use the class RollDie in a program:
// Program to test various operations of the class RollDie.

8

import java.util.*; //Line 1

public class TestProgRollDie //Line 2

{ //Line 3

static Scanner console = new Scanner(System.in); //Line 4

public static void main(String[] args) //Line 5

{ //Line 6

RollDie die1 = new RollDie(); //Line 7

RollDie die2 = new RollDie(); //Line 8

System.out.println("Line 9: die1: " + die1); //Line 9

System.out.println("Line 10: die2: " + die2); //Line 10

System.out.println("Line 11: After rolling "
+ "die1: " + die1.roll());

//Line 11

System.out.println("Line 12: After rolling "
+ "die2: " + die2.roll()); //Line 12

System.out.println("Line 13: Sum of the "
+ "numbers rolled by the dice is: "
+ (die1.getNum() + die2.getNum())); //Line 13