CS21: Homework #5

You should save your program for this assignment in your cs21/homework/05 directory. A skeleton version of the program will appear in this directory when you run update21 in a terminal window. The program handin21 will only submit files in this directory.

You may work with one partner on this assignment. If you work with a partner, put your name and the name of your partner in the list of authors in your program. Only one partner needs to run handin21 to submit the files for the group. Both partners will receive the same grade.

Introduction

For this assignment you will write a program that plays the game of Hangman. This program will be larger than any of the programs that you have written for previous assignments. Large programs require more up-front organization than small programs. You should design an outline of your program on paper first. Break the problem into smaller pieces that can be handled by functions. Then implement one function at a time, testing each function you write before you move on to the next function. If you carefully plan your solution, you should be able write a full solution in less than 100 lines of code.

Sample runs

In the sample run below, the user was able to successfully guess a secret word selected by the computer. Notice that in each turn the program displays the status of the secret word and the letters guessed so far, and then prompts the user to guess the next letter. Letters can be entered in upper or lower case. Notice that the letters guessed so far are displayed in alphabetic order in upper case. User input is shown in blue text.

Let's play hangman!  I will pick a secret word.
On each turn, you guess a letter.  If the letter is
in the secret word, I will show you where it appears.
You only get 6 incorrect guesses.  Good luck.

Secret word:  - - - - - - -
Letters guessed:
You have 6 wrong guesses left
Your guess: e

Secret word:  - - - - - - -
Letters guessed: E
You have 5 wrong guesses left
Your guess: I

Secret word:  - - - - - I -
Letters guessed: E I
You have 5 wrong guesses left
Your guess: n

Secret word:  - - - - - I N
Letters guessed: E I N
You have 5 wrong guesses left
Your guess: o

Secret word:  - - - - - I N
Letters guessed: E I N O
You have 4 wrong guesses left
Your guess: u

Secret word:  - U - - - I N
Letters guessed: E I N O U
You have 4 wrong guesses left
Your guess: m

Secret word:  - U M - - I N
Letters guessed: E I M N O U
You have 4 wrong guesses left
Your guess: s

Secret word:  - U M - - I N
Letters guessed: E I M N O S U
You have 3 wrong guesses left
Your guess: P

Secret word:  P U M P - I N
Letters guessed: E I M N O P S U
You have 3 wrong guesses left
Your guess: k

Secret word:  P U M P K I N

Congratulations, you guessed the word!
And you only had 3 wrong guesses

In the next sample run of the game the user is not able to guess the secret word. Notice that the program checks if the letter guessed has been guessed before, or if the user has entered an invalid letter. In either of these cases, the input is consider a wrong guess.

Let's play hangman!  I will pick a secret word.
On each turn, you guess a letter.  If the letter is
in the secret word, I will show you where it appears.
You only get 6 incorrect guesses.  Good luck.

Secret word:  - - - - - -
Letters guessed:
You have 6 wrong guesses left
Your guess: sagjkf
Please enter only a single letter

Secret word:  - - - - - -
Letters guessed:
You have 5 wrong guesses left
Your guess: 8
Please enter only a single letter

Secret word:  - - - - - -
Letters guessed:
You have 4 wrong guesses left
Your guess: R

Secret word:  - - R - - -
Letters guessed: R
You have 4 wrong guesses left
Your guess: S

Secret word:  - - R - - -
Letters guessed: R S
You have 3 wrong guesses left
Your guess: T

Secret word:  - - R - T -
Letters guessed: R S T
You have 3 wrong guesses left
Your guess: E

Secret word:  - - R - T E
Letters guessed: E R S T
You have 3 wrong guesses left
Your guess: L

Secret word:  - - R - T E
Letters guessed: E L R S T
You have 2 wrong guesses left
Your guess: E
You already guessed this letter

Secret word:  - - R - T E
Letters guessed: E L R S T
You have 1 wrong guesses left
Your guess: O

Sorry you lost!

Secret word: P I R A T E

Requirements

The secret word should be randomly chosen from a list of potential words. This list should contain at least 20 words and be stored in a file words.txt in your cs21/homework/05 directory.
Your program should ensure that invalid input from a user does not cause a run-time error.
Your program should check that the letter entered by a user has not been guessed before. If so, it reports the problem and counts the guess as a wrong guess.
On each turn, your program should list, in alphabetic order, the letters guessed so far.
The user is only allowed 6 wrong guesses.
If the user wins the game, the program should inform the user, display the number of wrong guesses the user made, and then exit.
If the user loses the game, the program should inform the user and display the secret word.
Your program must be broken up into a set of reasonable functions. Your main program should not be longer than approximately 30 lines of code.

Submit

Once you are satisfied with your programs, hand them in by typing handin21 in a terminal window.

CS21 HW5: Hangman