Microsoft WSH and VBScript Programming for the Absolute Beginner Part 33 pptx

300 ‘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 ‘Clear out the value of the strDisplayString variable Microsoft WSH and VBScript Programming for the Absolute Beginner, Second Edition strDisplayString = “” FlipString() End If End Select End If Loop DisplayGameResults() End Function Building the RetrieveWord() Function This function is designed to retrieve a randomly selected word to be used by the game. RetrieveWord() first selects a random number between 1 and 10, and then uses that number to retrieve a game word from the WordList() array. This function randomly retrieves a word from an array. Function RetrieveWord() Randomize intRandomNo = FormatNumber(Int(10 * Rnd)) RetrieveWord = astrWordList(intRandomNo) End Function This is a good place to perform another test. This time, open the temporary script that you created a little earlier and cut and paste it into the statements located in the previous func- tion. Paste the three statements into the temporary file, making them lines 3 though 5 in the script. Next, add the following statement as line 6: MsgBox RetrieveWord Save and run the script. Each time you execute the temporary script, a different randomly selected word should be displayed. If this is not the case, then something is wrong. Locate and fix any errors that may occur until the temporary script works as expected. Then, cut and paste any corrected script statements back into your Hangman script and move on to the next section. 301 Chapter 9 • Handling Script Errors 302 Building the InitialDisplayString() Function This function is used to display a series of underscore characters representing each letter that makes up the mystery game word: Function InitialDisplayString() ‘Create a loop that processes each letter of the word For intLetterCounter = 1 to Len(strGameWord) ‘Use underscore characters to display a string representing each ‘letter InitialDisplayString = InitialDisplayString & “_ “ Next End Function You can run a quick test of this function by creating a new temporary VBScript, cutting and pasting the statements from within this function into the temporary script, and modifying it. For intLetterCounter = 1 to Len(“DOG”) ‘Use underscore characters to display a string representing each letter InitialDisplayString = InitialDisplayString & “_ “ Next MsgBox InitialDisplayString You should see three underscore characters separated by blank spaces, indicating the length of the word. If anything is wrong, fix it and then copy the corrected statement(s) back into the Hangman script. Building the FirstLevelValidation() Function The FirstLevelValidation() function, shown next, ensures that the player is providing valid input. It checks to make sure that the player typed in something, that the player did not type in more than one character, and that a number was not provided as input. ‘Validate the player’s input Function FirstLevelValidation() ‘See if the player clicked on Cancel or failed to enter any input If strChoice = “” Then Microsoft WSH and VBScript Programming for the Absolute Beginner, Second Edition 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 Building the SecondLevelValidation() Function Like the previous function, the SecondLevelValidation() function, shown here, performs additional tests on the player’s guess to make sure that the player is not trying to guess the same letter twice. 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 303 Chapter 9 • Handling Script Errors 304 Building the TestLetterGuess() Function The TestLetterGuess() function, shown here, checks to see whether the letter is part of the word and keeps track of missed guesses. If the total number of missed guesses equals 6, then this function assigns a value of False to the blnWordGuessed variable. This variable is a flag that is later checked to see whether the player has lost the game. 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 Building the NonGuessedString() Function This game displays as a string the letters that make up the game’s mystery word and uses VBScript string manipulation functions to control the display of correctly and incorrectly guessed letters. As I was creating the game, I wanted an easy way of seeing what game word had been randomly selected and of tracking which letters had yet to be guessed. The NonGuessedString() function, shown next, builds a string that, if it were displayed, would show all the letters that make up the word, less the letters that the player has correctly guessed. This function gave me a tool for displaying how the game was keeping track of the game word. Function NonGuessedString() ‘Loop through the temporary string For intLetterCounter = 1 to Len(strTempStringOne) Microsoft WSH and VBScript Programming for the Absolute Beginner, Second Edition ‘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 After I developed this function, I added the following statement as the last statement in the function: MsgBox “ **** = “ & strTempStringTwo This way, each time the function ran, I was able to see the contents of the string. For exam- ple, if the game word is DOG and the player has missed his or her first guess, this string would be displayed in a pop-up dialog as D O G. If the player then guessed the letter O, then the string would display as D_G the next time this function ran. This function allowed me to visually track the progress of the string as the game ran and manipulated its contents. Building the CheckIfGameWon() Function The CheckIfGameWon() function checks to see whether the number of correctly guessed let- ters is equal to the length of the word. If this is the case, then the player has guessed all the letters that make up the word and won the game. 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 305 Chapter 9 • Handling Script Errors 306 Again, a well-placed MsgBox() in this function can be used to track the value of the blnCheckIfGameWon variable. Building the FlipString() Function The problem with the string produced by the NonGuessedString() function was that it dis- played a string in exactly the opposite format that I wanted to ultimately display. In other words, if the game word was DOG and the player had correctly guessed the letter O, then I wanted the game to display the word as _O_ and not as D_G. So I developed the FlipString() function. It loops through each character of the string created by the NonGuessedString() function and reverses the display of character data. 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 Here again, a well-placed statement that contains the MsgBox() function can be used to dis- play the activity of this function as it attempts to spin through and reverse the display of the letters that make up the game word. Building the DisplayGameResults() Function The DisplayGameResults() function, shown here, determines whether the player won or lost the game and is responsible for displaying the results of the game and for determining whether the player wants to play again. If the user elects to play another game, the strings Microsoft WSH and VBScript Programming for the Absolute Beginner, Second Edition that are used to track the status of the game word are blanked out and the PlayTheGame() function is called. Otherwise, the function ends and processing control is passed back to the end of the current iteration of the PlayTheGame() function, which then returns control to the Main Processing Section where the SplashScreen() function is called. ‘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!” 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 Building the SplashScreen() Function The SplashScreen() function is the last function in the script. As you have seen in other games in this book, this function displays some information about the game and its creator. After this function is processed, the Main Processing Section executes the WScript.Quit() method, terminating the game’s execution. ‘This function displays the game splash screen Function SplashScreen() 307 Chapter 9 • Handling Script Errors 308 MsgBox “Thank you for playing VBScript Hangman © Jerry Ford 2002.” & _ vbCrLf & vbCrLf & “Please play again soon!”, , cTitlebarMsg End Function The Final Result By now you should have all the pieces and parts of the Hangman script assembled and ready for execution. Save your work and give it a shot. After you have everything working correctly, you can remove or comment out any of the extra statements that use the MsgBox() function to track the game’s intermediate results. ‘************************************************************************* ‘Script Name: Hangman.vbs ‘Author: Jerry Ford ‘Created: 02/30/02 ‘Description: This script demonstrates how to create a game of Hangman ‘ using VBScript and the WSH. ‘************************************************************************* ‘Initialization Section Option Explicit Const cTitlebarMsg = “VBScript HANGMAN” Dim strChoice, strGameWord, intNoMisses, intNoRight, strSplashImage Dim intPlayOrNot, strMsgText, intPlayAgain, strWrongGuesses Dim strRightGuesses, blnWordGuessed, intLetterCounter Dim strTempStringOne, strTempStringTwo, strWordLetter, strDisplayString Dim intFlipCounter, intRandomNo, strProcessGuess, blnGameStatus Dim strCheckAnswer Dim astrWordList(9) ‘Define an array that can hold 10 game words ‘Main Processing Section intPlayOrNot = DoYouWantToPlay() Microsoft WSH and VBScript Programming for the Absolute Beginner, Second Edition If intPlayOrNot = 6 Then ‘User elected to play the game FillArray() PlayTheGame() End If SplashScreen() WScript.Quit() ‘Procedure Section Function DoYouWantToPlay() ‘Display the splash screen and ask the user if he or she wants to play strSplashImage = Space(100) & “***********” & vbCrLf & _ “W E L C O M E T O “ & Space(68) & “*” & Space(18) & “*” & _ vbCrLf & Space(100) & “0” & Space(18) & “*” & vbCrLf & _ “V B S c r i p t H A N G M A N !” & Space(50) & “—||—” & _ Space(15) & “*” & vbCrLf & Space(99) & “/” & Space(1) & “\” & _ Space(17) & “*” & vbCrLf & Space(120) & “*” & vbCrLf & Space(120) & _ “*” & vbCrLf & space(113) & “ ******* “ & vbCrLf & _ “Would you like to play a game?” & vbCrLf & “ “ DoYouWantToPlay = MsgBox(strSplashImage, 36, cTitlebarMsg) End Function Function FillArray() ‘Add the words to the array astrWordList(0) = “AUTOMOBILE” astrWordList(1) = “NETWORKING” astrWordList(2) = “PRACTICAL” astrWordList(3) = “CONGRESS” astrWordList(4) = “COMMANDER” astrWordList(5) = “STAPLER” 309 Chapter 9 • Handling Script Errors . play again. If the user elects to play another game, the strings Microsoft WSH and VBScript Programming for the Absolute Beginner, Second Edition that are used to track the status of the game word. through the temporary string For intLetterCounter = 1 to Len(strTempStringOne) Microsoft WSH and VBScript Programming for the Absolute Beginner, Second Edition ‘Examine each letter in the word. Function The DisplayGameResults() function, shown here, determines whether the player won or lost the game and is responsible for displaying the results of the game and for determining whether the