310
astrWordList(6) = “ENTERPRISE”
astrWordList(7) = “ESCALATION”
astrWordList(8) = “HAPPINESS”
astrWordList(9) = “WEDNESDAY”
End Function
Function PlayTheGame()
‘Initialize variables displayed by the game’s initial pop-up dialog
intNoMisses = 0
intNoRight = 0
strWrongGuesses = “”
strRightGuesses = “”
‘Get the game a mystery word
strGameWord = RetrieveWord()
‘Call function that formats the initial pop-up dialog’s display string
strDisplayString = InitialDisplayString()
strTempStringOne = strGameWord
‘Let the player start guessing
Do Until intNoMisses = 6
‘Collect the player’s guess
strChoice = InputBox(vbCrLf & vbTab & strDisplayString & vbCrLf & _
vbCrLf & vbCrLf & “No. of Misses: “ & intNoMisses & _
“ “ & vbTab & “Incorrect:” & strWrongGuesses & vbCrLf _
& vbCrLf & vbCrLf & _
“Type a letter and click on OK.” , cTitleBarMsg)
‘Determine if the player has quit
If strChoice = “” Then
Exit Function
End If
Microsoft WSH and VBScript Programming for the Absolute Beginner, Second Edition
strProcessGuess = FirstLevelValidation()

‘The player wants to quit the game
If strProcessGuess = “ExitFunction” Then
Exit Function
End If
‘The player typed invalid input
If strProcessGuess <> “SkipRest” Then
strProcessGuess = SecondLevelValidation()
Select Case strProcessGuess
Case “DuplicateWrongAnswer”
MsgBox “Invalid: You’ve already guessed this incorrect letter.”
Case “DuplicateRightAnswer”
MsgBox “Invalid: You’ve already guessed this correct letter.”
Case Else
strCheckAnswer = TestLetterGuess()
If strCheckAnswer <> “IncorrectAnswer” Then
‘Reset the value of variable used to build a string containing
‘the interim stage of the word as currently guessed by player
strTempStringTwo = “”
NonGuessedString()
‘Check to see if the player has guessed the word
blnGameStatus = CheckIfGameWon()
If blnGameStatus = “True” Then
blnWordGuessed = “True”
Exit Do
End If
‘Set the value of the temporary string equal to the string
‘created by the Previous For Next loop
strTempStringOne = strTempStringTwo
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312
‘Clear out the value of the strDisplayString variable
strDisplayString = “”
FlipString()
End If
End Select
End If
Loop
DisplayGameResults()
End Function
‘This function randomly retrieves a word from an array
Function RetrieveWord()
Randomize
intRandomNo = FormatNumber(Int(10 * Rnd))
RetrieveWord = astrWordList(intRandomNo)
End Function
Function InitialDisplayString()
‘Create a loop that processes each letter of the word
For intLetterCounter = 1 to Len(strGameWord)
‘Use underscore characters to display string representing each letter
InitialDisplayString = InitialDisplayString & “_ “
Next
End Function
‘Validate the player’s input
Function FirstLevelValidation()
Microsoft WSH and VBScript Programming for the Absolute Beginner, Second Edition
‘See if the player clicked on Cancel or failed to enter any input
If strChoice = “” Then
FirstLevelValidation = “ExitFunction”
Exit Function

End If
‘Make sure the player only typed 1 letter
If Len(strChoice) > 1 Then
MsgBox “Invalid: You must only enter 1 letter at a time!”
FirstLevelValidation = “SkipRest”
Else
‘Make sure the player did not type a number by accident
If IsNumeric(strChoice) = “True” Then
MsgBox “Invalid: Only letters can be accepted as valid input!”
FirstLevelValidation = “SkipRest”
Else
FirstLevelValidation = “Continue”
End If
End If
End Function
Function SecondLevelValidation()
‘Check to see if this letter is already on the incorrectly guessed list
If Instr(1, strWrongGuesses, UCase(strChoice), 1) <> 0 Then
SecondLevelValidation = “DuplicateWrongAnswer”
Else
‘Check to see if this letter is already on the correctly guessed list
If Instr(1, strRightGuesses, UCase(strChoice), 1) <> 0 Then
SecondLevelValidation = “DuplicateRightAnswer”
End If
End If
End Function
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314
Function TestLetterGuess()

If Instr(1, UCase(strGameWord), UCase(strChoice), 1) = 0 Then
‘Add the letter to the list of incorrectly guessed letters
strWrongGuesses = strWrongGuesses & “ “ & UCase(strChoice)
‘Increment the number of guesses that the player has made by 1
intNoMisses = intNoMisses + 1
‘If the player has missed 6 guesses then he has used up all chances
If intNoMisses = 6 Then
blnWordGuessed = “False”
End If
TestLetterGuess = “IncorrectGuess”
Else
TestLetterGuess = “CorrectGuess”
End If
End Function
Function NonGuessedString()
‘Loop through the temporary string
For intLetterCounter = 1 to Len(strTempStringOne)
‘Examine each letter in the word one at a time
strWordLetter = Mid(strTempStringOne, intLetterCounter, 1)
‘Otherwise add an underscore character indicating a nonmatching guess
If UCase(strWordLetter) <> UCase(strChoice) Then
strTempStringTwo = strTempStringTwo & strWordLetter
Else
‘The letter matches player’s guess. Add it to the temporary string
intNoRight = intNoRight + 1
strRightGuesses = strRightGuesses & “ “ & UCase(strChoice)
strTempStringTwo = strTempStringTwo & “_”
End If
Next
End Function

Microsoft WSH and VBScript Programming for the Absolute Beginner, Second Edition
Function CheckIfGameWon()
‘Check and see if the player has guessed all the letters that make up
‘the word. If so, set indicator variable and exit the Do Until loop
If intNoRight = Len(strGameWord) Then
CheckIfGameWon = “True”
End If
End Function
Function FlipString()
‘Spin through and reverse the letters in the strTempStringTwo variable
‘In order to switch letters to underscore characters and underscore
‘characters to the appropriate letters
For intFlipCounter = 1 to Len(strTempStringTwo)
‘Examine each letter in the word one at a time
strWordLetter = Mid(strTempStringTwo, intFlipCounter, 1)
‘Replace each letter with the underscore character
If strWordLetter <> “_” Then
strDisplayString = strDisplayString & “_ “
Else
‘Replace each underscore with its appropriate letter
strDisplayString = strDisplayString & _
Right(Left(strGameWord,intFlipCounter),1) & “ “
End If
Next
End Function
‘Determine if the player won or lost and display game results
Function DisplayGameResults()
‘Select message based on whether or not the player figured out the word
If blnWordGuessed = “True” Then
strMsgText = “Congratulations, You Win!”

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316
Else
strMsgText = “Sorry, You Lose.”
End If
‘Display the results of the game
intPlayAgain = MsgBox(vbCrLf & “The word was: “ & _
UCase(strGameWord) & vbCrLf & vbCrLf & vbCrLf & strMsgText & _
vbCrLf & vbCrLf & vbCrLf & _
“Would you like to play again?” , 4, cTitleBarMsg)
‘Find out if the player wants to play another game
If intPlayAgain = 6 Then
‘If the answer is yes reset the following variables & start a new game
strDisplayString = “”
strTempStringTwo = “”
PlayTheGame()
End If
End Function
‘This function displays the game splash screen
Function SplashScreen()
MsgBox “Thank you for playing VBScript Hangman © Jerry Ford 2002.” & _
vbCrLf & vbCrLf & “Please play again soon!”, , cTitlebarMsg
End Function
Although the script, as shown here, should work just fine, there is always the chance that
you’ll miss something or make a typo when creating it. After all, this is a rather large script
and with size generally comes complexity, which only increases the probability that some-
thing will go wrong.
After you’ve thoroughly tested the script, give it to somebody else to test. Ask your tester to
play the game according to the rules, and then ask him to play it by not following the rules.

Ask your tester to keep track of any problems that he experiences and to record any error mes-
sages that might appear. If an error does appear, get the player to write down exactly what
steps he took, so that you can go back and generate the error yourself and begin debugging it.
Microsoft WSH and VBScript Programming for the Absolute Beginner, Second Edition
Summary
In this chapter, you learned how to add programming logic to your scripts to help deal with
errors. This included everything from rewriting error messages to making them more user
friendly to ignoring errors or creating error-handling routines that allow your scripts to
recover from certain types of errors. I also provided advice that can help you prevent errors
from occurring in the first place, or at least minimize their number. Finally, I reviewed the
different ways of reporting errors that cannot otherwise be handled. On top of all this, you
learned how to create the Hangman game and how to test it at various stages of development.
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Chapter 9 • Handling Script Errors
C HALLENGES
1. Make the Hangman game more fun and interesting by expanding the pool of
game words.
2. Improve the Hangman program by keeping track of the number of games played
during a session and displaying a summary of the overall number of times the
player won and lost.
3. Add logic to the Hangman game that allows you to track its use. For example,
prompt the player for his or her name, and then write a message to either a log
file or the Windows application event log each time the player plays the game.
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Using the Windows
Registry to Configure
Script Settings
10
CHAPTER
S

o far, all the scripts you’ve worked with in this book collected configura-
tion information and input from three places: from the user, from within
the script itself, or from INI files. In this chapter, I’ll show you another
option for externalizing script settings by storing and retrieving configuration
data using the Windows Registry. As a bonus, in the chapter’s game project, I’ll
also demonstrate how to retrieve input data from files. Specifically, you will
• Review the overall organization and design of the Windows Registry
• Learn how to programmatically create, modify, and delete Registry keys
and values
• Learn how to read data stored in external files and process it as input
Project Preview: Part 2 of the Hangman Game
In this chapter, you will enhance the Hangman game that you began developing
in Chapter 9, “Handling Script Errors.” You’ll begin by creating a new setup script
that uses the Windows Registry to store the location of the folder where new
external word files are stored. You’ll then modify the Hangman script by remov-
ing the array that stores game words within the script and tweaking the script so
that it retrieves words from the external word files. You will also modify the
game to allow the player to select the category of words to play in. For example,
you might want to create different word files for categories such as Foods or Places.
CHAPTER