11. Explanation on GuessingRandomNumber class

Okay so I've just posted the class code here in case you didn't want to download it over at the source code page.  Copy and paste it then look at the comments, they will explain what is going on!!!

1. import java.util.Scanner;
2. import java.util.Random;
4. public class GuessRandomNumber
5. {
6.     public static void main(String[] args)
7.     {
8.         //Create a new scanner object called input
9.         Scanner input = new Scanner(System.in);
10.         //Create a new random object called generator
11.         Random generator = new Random();
12.         //Here we will count how many guesses the user has
13.         int guessCounter = 0;
14.         //This boolean is true if the user hasn't won
15.         boolean userHasNotWon = true;
16.         //This sets the number that the user is trying to guess to a number from 0-20
17.         int answer = generator.nextInt(20);
18.         //This while loop will run while the user hasn't won
19.         while(userHasNotWon == true)
20.         {
21.             //Here, we ask the user from between 0-20 and assign it to an int called guess
22.             System.out.print("Guess a number between 0 and 20: ");
23.             int guess = input.nextInt();
24.             //If the guess is over twenty then we tell the user
25.             if(guess > 20) {
26.                 System.out.println("The number can't be more than twenty!");
27.             }
28.             //If the guess is less than 0 then we tell the user
29.             if(guess < 0) {
30.                 System.out.println("The number can't be less than zero!");
31.             }
32.             //If the guess is in the right range then we check whether they were right or not
33.             if(guess >= 0 && guess <= 20) {
34.                 //If the guess is too high then we tell the user and increment the guess counter by one
35.                 if (guess < answer) {
36.                     System.out.println("Too low");
37.                     guessCounter += 1;
38.                 }
39.                 //If the guess is too low then we tell the user and increment the guess counter by 1
40.                 if (guess > answer) {
41.                     System.out.println("Too high");
42.                     guessCounter +=1;
43.                 }
44.                 /**If the user guesses the right number then we tell them they won and
45.                 tell them how many times they had to guess**/
46.                 if (guess == answer) {
47.                     System.out.println("YOU WIN!!! And you guessed " + guessCounter + " times!!!");
48.                     userHasNotWon = false;
49.                 }
50.             }
51.         }
52.     }
53. }