Lab 8: The Hanging Man

Due by the end of class

The classic game of Hangman presents a player with an unknown word consisting of a known number of letters. The player must then make guesses about which letters of the alphabet make up the word. As each guess is made, the spaces that represent the letters of the word are filled in if a guess correctly identifies letters in the word. In general, the player has a limited number of incorrect guesses. As guesses run out, the countdown is often represented by drawing additional body parts suspended from a gallows. When the entire body has been drawn, the player has run out of guesses and loses. If the player is able to guess all of the letters in the word before running out of guesses, he or she wins.

Our goal is to implement a version of the game that randomly picks a word from a dictionary file. Our game will always give the player six incorrect guesses, but it will not draw a man being hanged to represent the remaining chances.

Specification

Create a project called Lab8. Add a class called Hangman. This lab is long, but each part of the lab is relatively straightforward.

The program should work with any text file that lists unique words, each on separate lines, but we are providing the following dictionary file. Right-click on the link below and save it into your project folder Lab8 (but not in the src or bin sub-folders).

dict2.txt

Opening the file

Initialize a Scanner for reading from the keyboard. Declare another Scanner called file for reading from the file, but set it to null rather than creating a Scanner object.

Similar to examples from class, create a while loop that runs as long as file is null. Inside this loop and within a try block, ask the user to enter a word file name and read it in. Set file equal to a new Scanner object created from a new File object created from this name.

Below the try block but still within the loop, make a catch clause to catch exceptions of type FileNotFoundException. Within this clause, print out File not found! In this way, the user will be given an error message if he or she tries to open a file that doesn't exist. The loop will keep running until file points at a real (non-null) Scanner object.

Reading the words

Now that the file is open, ask the user to enter the length of the word and store it into an integer variable named length.

We haven't discussed them in class, but an ArrayList is a Java class that allows us to store an arbitrarily large number of items. Declare and instantiate a new ArrayList to hold words as follows.

ArrayList<String> words = new ArrayList<String>();

Then, loop as long as there's another line in the file (using the hasNextLine() method in your Scanner object). Read the line (using the nextLine() method) and convert this input to upper case. If the length of this line (a word) is length (the length the user chose), add it to the ArrayList as follows.

words.add(word);

Close the file.

Setting up the game

Now, we have all the words of the appropriate length stored in the list called words. We want to select a random word from this list. Create a Random object. Call its nextInt() method with words.size() as its parameter. Doing so will generate a random integer between 0 and words.size() - 1. Call this number choice. To get the word from the list at that location, use the following code.

String target = words.get(choice);

There are a few other variables we need to set up to make the game work. Refer to the following table.

Type	Variable	Initial Value	Meaning
`int`	`chances`	`6`	Remaining incorrect guesses allowed
`boolean`	`found`	`false`	Remaining incorrect guesses allowed
`char[]`	`letters`	An array of length `length` (the length of `target`). Use a `for` loop to fill it initially with underscore (`'_'`) characters.	A display for the letters in the word that are currently known
`boolean[]`	`used`	An array of length 26. Simply creating an array of 26 `boolean` values automatically initializes them all to `false`, which we want.	Which letters have been guessed

Playing the game

With all the variables set up properly, the code to play the game should follow the pattern below. Be sure to refer to the Sample Output below, and try to match the output as closely as possible.

While chances is greater than zero and found is not true:

Print out Letters:
Loop through all the characters in letters and print them out with a space afterward
Print a newline
Print the number of chances that remain
Ask the user to enter a guess
Read in a String, convert it to upper case, and store the first character in it into a variable called letter
Subtract 'A' from this letter to get an index
If the index in used is true:
- Print Letter already used!
Otherwise:

Mark the index in used true
If target.indexOf(letter) is not -1 (the letter must be in target):

Print Correct guess!
Set an integer variable underscores to 0
Loop over all the indexes in letters:
- If the character at the corresponding index in target matches letter:
- Otherwise, if the character at the corresponding index in letters is still an underscore ('_'):
If after the loop, undercores is still zero:

There must have been no underscores left, so all letters were found, so set found to true

Otherwise, letter is not in target:

Print Incorrect guess!
Decrement chances by one

Winning and losing

There are two possible ways to leave the loop (other than bad input crashing the program, which you're not required to deal with in this lab): Either the user ran out of chances or found the word.

If found is true, the user found the word, so print out You win! Otherwise, print You lose!

Either way, print out what target was.

Sample Output

Below is sample output from the program. The user selects a dictionary file called dict2.txt and picks a word length of 8. The user makes a number of guesses and is barely able to identify the word "BREAKAGE."

Enter word file name: dict2.txt
Enter length of word: 8
Letters: _ _ _ _ _ _ _ _ 
6 chances remain.
Enter guess: E
Correct guess!
Letters: _ _ E _ _ _ _ E 
6 chances remain.
Enter guess: T
Incorrect guess!
Letters: _ _ E _ _ _ _ E 
5 chances remain.
Enter guess: A
Correct guess!
Letters: _ _ E A _ A _ E 
5 chances remain.
Enter guess: N
Incorrect guess!
Letters: _ _ E A _ A _ E 
4 chances remain.
Enter guess: S
Incorrect guess!
Letters: _ _ E A _ A _ E 
3 chances remain.
Enter guess: H
Incorrect guess!
Letters: _ _ E A _ A _ E 
2 chances remain.
Enter guess: R
Correct guess!
Letters: _ R E A _ A _ E 
2 chances remain.
Enter guess: C
Incorrect guess!
Letters: _ R E A _ A _ E 
1 chances remain.
Enter guess: B
Correct guess!
Letters: B R E A _ A _ E 
1 chances remain.
Enter guess: K
Correct guess!
Letters: B R E A K A _ E 
1 chances remain.
Enter guess: G
Correct guess!
You win! The word was "BREAKAGE."

In this second sample output, the user selects the same dictionary file dict2.txt but picks a word length of 4. The user makes a number of guesses but fails to identify the word "BOAR" before using up six incorrect guesses.

Enter word file name: dict2.txt
Enter length of word: 4
Letters: _ _ _ _ 
6 chances remain.
Enter guess: E
Incorrect guess!
Letters: _ _ _ _ 
5 chances remain.
Enter guess: T
Incorrect guess!
Letters: _ _ _ _ 
4 chances remain.
Enter guess: A
Correct guess!
Letters: _ _ A _ 
4 chances remain.
Enter guess: O
Correct guess!
Letters: _ O A _ 
4 chances remain.
Enter guess: N
Incorrect guess!
Letters: _ O A _ 
3 chances remain.
Enter guess: S
Incorrect guess!
Letters: _ O A _ 
2 chances remain.
Enter guess: H
Incorrect guess!
Letters: _ O A _ 
1 chances remain.
Enter guess: R
Correct guess!
Letters: _ O A R 
1 chances remain.
Enter guess: D
Incorrect guess!
You lose! The word was "BOAR."

Turn In

Turn in your code by uploading Hangman.java from the Lab8\src folder inside your workspace folder to Blackboard. Do not upload the entire project. I only want the Hangman.java file.

All work must be done individually. Never look at someone else's code. Please refer to the course policies if you have any questions about academic integrity. If you have trouble with the assignment, I am always available for assistance.