Page 226 - Learn To Program With Scratch

secretWord=across
displayWord=??????
answer=r

  
Iteration char char temp
1 a ? ?
2 c ? ??
 3 r r ??r
 4 o ? ??r?
5 s ? ??r??
6 s ? ??r???



Figure 8-27: The ProcessAnswer procedure

The loop examines each letter of secretWord, using pos as an index.
If the examined letter (saved in char) equals the guessed letter (saved in
Scratch’s built-in answer variable), the gotLetter flag is set to 1. Otherwise,
the char variable is set to the letter at the corresponding position in the
displayWord variable. Either way, the script adds char to the end of temp, as
illustrated in Figure 8-27 (right).
When the loop terminates, the displayWord variable will contain the
six letters to be displayed on the Stage, taking the user’s most recent guess
into account. The loop also tracks the number of question marks in the
display string. If there are none, then the user has successfully guessed
the secret word.
When ProcessAnswer returns, the NewGame message handler checks
gotLetter to see whether the player guessed correctly. If not, it will call
ProcessWrongGuess, shown in Figure 8-28.
This procedure broadcasts WrongGuess to notify the Hangman sprite to
show its next costume, and then it decrements the number of remaining
guesses by 1. If the user is out of guesses, the script reveals the secret word
and ends the game. Otherwise, it broadcasts an Update message to show how
many trials the player has left.

204 Chapter 8
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