Hangman

1
Hangman

• Project 3
• Wed, Oct 22, 2003
• Due Wed, Oct 29, 2003

2
Hangman Project

• This program will play the game of Hangman.
• The program chooses a secret word at random.
• The player guesses letters until either he
  guesses the word or he gets hanged.
• Nowadays this game is called Wheel of Fortune,
  except they dont hang you.

3
Variables

• word the secret word.
• Example CALENDAR
• puzzle the mixture of underscores and correct
  guesses, so far.
• Example _ A _ E N _ A R
• letter the guessed letter.
• Example N
• numOfBadGuesses the number of bad guesses, so
  far.

4
Program Functions

• The program will have six functions
• int main()
• void printWelcome()
• string createUnderscores(const string word)
• int substituteLetter(string puzzle, const
  string word, char letter)
• void drawGallows(int numOfBadGuesses)
• string getWord()

5
Problems in main()

• A while loop controls whether to play another
  game.

// Initialize some stuff while
(next-game-condition) // Play another game
6
Problems in main()

• A while loop controls when to end a particular
  game.

// Initialize some stuff while
(continue-game-condition) // Process the next
guess
7
Problems in main()

• You may use a while loop to reject guesses that
  use a letter that was already guessed.

while (guessed-letter-was-already-guessed) //
Print an error message // Get a new guess
8
Problems in createUnderscores()

• The underscores must be separated by blanks.
• Begin with an empty string of underscores.
• Use a for loop.
• For each letter in the secret word, concatenate
  "_ " to the string of underscores.
• Thus, the underscores will be in positions 0, 2,
  4, 6, 8, and so on.

9
Outline of createUnderscores()
string createUnderscores(const string word) //
Initialize underscore string // for loop, once
for each letter in word // For each
letter in word, concatenate "_ " to underscore
string // Return underscore string
10
Problems in substituteLetter()

• Use a for loop to compare each letter of the
  secret word to the guessed letter.
• If the guessed letter matches the letter in
  position i of the secret word, we must replace
  the i-th underscore with that letter.
• What is the position of the i-th underscore in
  the string of underscores?

11
Problems in substituteLetter()

• Also, to guarantee a proper match, convert the
  user's guess to uppercase, in case he entered it
  in lowercase.

12
Outline of substituteLetter()
int substituteLetter(string puzzle, const
string word, char letter) // for loop, once
for each letter in word // For each
letter in word, compare it to the
guessed letter // If they match,
// Replace the corresponding underscore
// Count the match //
Return the number of matching letters
13
Problems in drawGallows()

• Make a separate decision for each line of the
  drawing, depending on the number of bad guesses.
• Depending on the number of possibilities, use
  either a switch statement or a multi-way if
  statement.

14
Problems in drawGallows()

• For example, the fourth line will be one of the
  following strings
• /
• /
• /\
• depending on whether the number of bad guesses
  is less than 2, equal to 2, equal to 3, or
  greater than 3.

15
Problems in drawGallows()

• Printing the backslash \ presents a technical
  problem.
• The backslash is used to indicate an escape
  character.
• It is used to indicate special control
  characters
• '\n' is a newline character.
• '\b' is a backspace character.

16
Problems in drawGallows()

• For example, the statement
• cout ltlt "abc/\npq" ltlt endl
• will print abc/ on one line and pq on another.
• To print a backslash, we must print the character
  '\\'.
• Thus, the statement
• cout ltlt "abc/\\npq" ltlt endl
• will print abc/\npq, on one line.

17
The Backslash Problem

• This also is a problem in writing path names such
  as
• "C\My Documents\prog.cpp".
• That is why, in C programs, we use the regular
  slash /.
• "C/My Documents/prog.cpp".
• However, sometimes you will see it written as
• "C\\My Documents\\prog.cpp".