Microsoft WSH and VBScript Programming for the Absolute Beginner Part 17 ppt

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Microsoft WSH and VBScript Programming for the Absolute Beginner, Second Edition
Creating a Splash Screen
As I said, adding a splash screen to your script gives you an opportunity to display your Web
site, game instructions, or other information you think will be useful to the user.
The following statements show one way of building a splash screen. The
StrWelcomeMsg vari-
able is used to define the text that will be displayed in the splash screen. The message text
to be displayed is formatted using VBScript string constants to make it more attractive.
‘Specify the message to be displayed in the initial splash screen
strWelcomeMsg = “Welcome to the story of ” & vbCrLf & _
vbCrLf & “CCC” & space(14) & “A” & vbCrLf & _
“C” & space(17) & “AAA” & vbCrLf & _
“CCCaptain A Adventure gets his super powers” & _
vbCrLf
‘ Welcome the user to the story
MsgBox strWelcomeMsg, vbOkOnly + vbExclamation, cGameTitle
Finally, the VBScript MsgBox() function is used to display the splash screen. In this case, the
vbOkOnly + vbExclamation MsgBox() constants instruct VBScript to display only the OK but-
ton and the exclamation mark graphic on the pop-up dialog. In addition, the
cGameTitle
constant has been added to display the script’s custom title bar message.
Collecting User Input
The next five lines of code, shown next, use the VBScript InputBox() function to collect data
provided by the user. This code contains the following five questions/instructions:
• What is your name?
• Name a place you would like to visit.
• Name a strange object.
• Type the name of a close friend.
• Type the name of your favorite dessert.
‘Collect story information from the user

strName = InputBox(“What is your name?”, cGameTitle,”Joe Blow”)
strVacation = InputBox(“Name a place you would like to visit.”, _
cGameTitle,”Nevada”)
strObject = InputBox(“Name a strange object.”, cGameTitle,”Soda Can”)
strFriend = InputBox(“Type the name of a close friend.”, _
cGameTitle,”Barney”)
strFood = InputBox(“Type the name of your favorite dessert.”, _
cGameTitle,”Pickle”)
Notice that the user is only given a little bit of information about the type of information
the script is looking for. This is intentional, and is meant to provide a certain amount of
unpredictability to the story line.
You may have also noticed the final argument on each of the
InputBox() statements. I have
added the argument so that each dialog that is displayed by the script will automatically
display a default answer. Providing a default answer in this way helps the user, by giving an
idea of the kind of information you’re trying to collect.
Assembling and Displaying the Story
The last step in putting together the Captain Adventure script is to assemble the story. This
is done by typing out the story’s text while inserting references to the script’s variables at
the appropriate locations in the story. In addition, the
vbCrLf string constant is used to
improve the display of the story.
The entire story is assembled as a single string, which is stored in a variable called
Story.
Finally, the completed story is displayed using the VBScript
MsgBox() function.
‘ Assemble the Captain Adventure story
strStory = “Once upon a time ” & vbCrLf & vbCrLf & _
strName & “ went on vacation in the far away land of “ & strVacation & _
“. A local tour guide suggested cave exploration. While in the cave “ & _

strName & “ accidentally became separated from the rest of the tour “ & _
“group and stumbled into a part of the cave never visited before. “ & _
“It was completely dark. Suddenly a powerful light began to glow. “ & _
strName & “ saw that it came from a mysterious “ & strObject & “ “ & _
“located in the far corner of the cave room. “ & strName & “ picked “ & _
“it up and a flash of light occurred and “ &strName & “ was “ & _
“instantly transported to a far away world. There in front of him “ & _
“was “ & strFriend & “, the ancient God of the legendary cave “ & _
“people. “ & strFriend & “ explained to “ & strName & “ that “ & _
“destiny had selected him to become Captain Adventure! He was “ & _
“then returned to Earth and told to purchase a Winnebago and travel “ & _
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Chapter 4 • Constants, Variables, and Arrays
142
“the countryside looking for people in need of help. To activate “ & _
“the superpowers bestowed by “ & strFriend & “ all that “ & strName & _
“had to do was pick up the “ & strObject & “ and say “ & strFood & _
“three times in a row.” & vbCrLf & vbCrLf & _
“The End”
‘Display the story
MsgBox strStory, vbOkOnly + vbExclamation, cGameTitle
The Final Result
Okay, now that you’ve written all the various parts of the programs, put them all together
into a single script, as follows:
‘*************************************************************************
‘Script Name: Captain Adventure.vbs
‘Author: Jerry Ford
‘Created: 02/28/02
‘Description: This script prompts the user to answer a number of questions
‘and then uses the answers to create a comical action adventure story.

‘*************************************************************************
‘Perform script initialization activities
Option Explicit
‘Specify the message to appear in each pop-up dialog title bar
Const cGameTitle = “Captain Adventure”
‘Specify variables used by the script
Dim strWelcomeMsg, strName, strVacation, strObject, strFriend
Dim strFood, strStory
‘Specify the message to be displayed in the initial splash screen
strWelcomeMsg = “Welcome to the story of ” & vbCrLf & _
vbCrLf & “CCC” & space(14) & “A” & vbCrLf & _
“C” & space(17) & “AAA” & vbCrLf & _
“CCCaptain A Adventure gets his super powers” & _
vbCrLf
Microsoft WSH and VBScript Programming for the Absolute Beginner, Second Edition
‘ Welcome the user to the story
MsgBox strWelcomeMsg, vbOkOnly + vbExclamation, cGameTitle
‘Collect story information from the user
strName = InputBox(“What is your name?”, cGameTitle,”Joe Blow”)
strVacation = InputBox(“Name a place you would like to visit.”, _
cGameTitle,”Nevada”)
strObject = InputBox(“Name a strange object.”, cGameTitle,”Soda Can”)
strFriend = InputBox(“Type the name of a close friend.”, _
cGameTitle,”Barney”)
strFood = InputBox(“Type the name of your favorite dessert.”, _
cGameTitle,”Pickle”)
‘ Assemble the Captain Adventure story
strStory = “Once upon a time ” & vbCrLf & vbCrLf & _
strName & “ went on vacation in the far away land of “ & strVacation & _
“. A local tour guide suggested cave exploration. While in the cave “ & _

strName & “ accidentally became separated from the rest of the tour “ & _
“group and stumbled into a part of the cave never visited before. “ & _
“It was completely dark. Suddenly a powerful light began to glow. “ & _
strName & “ saw that it came from a mysterious “ & strObject & “ “ & _
“located in the far corner of the cave room. “ & strName & “ picked “ & _
“it up and a flash of light occurred and “ &strName & “ was “ & _
“instantly transported to a far away world. There in front of him “ & _
“was “ & strFriend & “, the ancient God of the legendary cave “ & _
“people. “ & strFriend & “ explained to “ & strName & “ that “ & _
“destiny had selected him to become Captain Adventure!. He was “ & _
“then returned to Earth and told to purchase a Winnebago and travel “ & _
“the countryside looking for people in need of help. To activate “ & _
“the superpowers bestowed by “ & strFriend & “ all that “ & strName & _
“had to do was pick up the “ & strObject & “ and say “ & strFood & _
“three times in a row.” & vbCrLf & vbCrLf & _
“The End”
‘Display the story
MsgBox strStory, vbOkOnly + vbExclamation, cGameTitle
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Chapter 4 • Constants, Variables, and Arrays
144
Now, run the script and test it to make sure that everything works as expected. Be aware that
this script pushes the string length allowed by VBScript to the limit. If the information that
you supply to the script is too long, some of the story may end up truncated.
Summary
You covered a lot of ground in this chapter. You now know how to define and work with con-
stants and variables, including VBScript’s built-in constants and Windows environment
variables. In addition, you learned how to apply VBScript string constants to script output
to control the manner in which output is displayed. You also learned about the VBScript
variant and how to use built-in VBScript functions to convert data from one variant subtype

to another. Finally, you learned how to store related collections of data in arrays for more
efficient storage and processing, and to develop scripts that can process input passed to
them at execution time.
Microsoft WSH and VBScript Programming for the Absolute Beginner, Second Edition
C HALLENGES
1. Modify the Captain Adventure story by collecting additional user input and
adding more text to the story line.
2. Try using an array to store the user input collected in the Captain Adventure
story instead of storing data in individual variables.
3. Develop your own story for someone you know, and e-mail it to your friend as a
sort of living greeting card.
4. Experiment with the VBScript string constants when developing your own story
to improve the format and presentation of your story’s output.
Conditional
Logic
5
CHAPTER
E
very programming language allows you to perform tests between two or
more conditions. This capability is one of the cornerstones of programming
logic. It lets you develop scripts that collect input from the user or the
user’s computer and compare it to one or more conditions. Using the results of
the tests, you can alter the execution of your scripts and create dynamic scripts that
can adjust their execution according to the data with which they’re presented.
By the time you have completed this chapter, you’ll know how to:
• Write scripts that test two conditions
• Write scripts that can test two or more conditions against a single value
• Write scripts that can test for a variety of different types of conditions
• Write scripts that work with a variety of built-in VBScript functions
Project Preview: The Star Trek Quiz Game

In this chapter, you’ll create a game that administers and scores a quiz based on
various Star Trek TV shows and movies. The game asks the player a series of ques-
tions and then assigns a rank of Ensign, Lieutenant, Lieutenant Commander,
Commander, Captain, or Admiral, based on the player’s final score. Besides dis-
playing the final results, the game also creates a report that shows every question
that was asked, the player’s answer, the correct answer for any incorrectly
answered question, the total number of questions answered correctly, and the
player’s assigned rank.
CHAPTER
146
Figures 5.1 through 5.4 show some of the interaction between the player and the game.
During the development of this game, you will learn how to apply sophisticated conditional
logic. In addition, you’ll also learn how to work with a number of built-in VBScript functions.
Microsoft WSH and VBScript Programming for the Absolute Beginner, Second Edition
Figure 5.1
The game’s splash
screen invites
the user to take
the quiz.
Figure 5.2
This dialog
appears if the
user decides
not to play.
Figure 5.3
This figure shows
an example of
the types of
questions asked
by the game.

Figure 5.4
When the player
finishes the
questions, his
or her score is
tallied, and a rank
is assigned based
on the number
of questions
correctly
answered.
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Chapter 5 • Conditional Logic
Examining Program Data
In any programming language, you need to be able to test whether a condition is true or
false to develop complex logical processes. VBScript provides two different statements that
perform this function. These statements are
•
If. A statement that allows or skips the execution of a portion of a program based on
the results of a logical expression or condition.
•
Select Case. A formal programming construct that allows a programmer to visually
organize program flow when dealing with the results of a single expression.
You’ve already seen short demonstrations of the If statement in earlier chapters of this book.
This is because even the simplest scripts require some form of conditional logic.
The power and importance of these two statements cannot be overstated. For example, let’s
say you took a job from someone without knowing exactly what you’d be paid, and now
you’re finished with the job and are waiting to be paid. As you’re waiting, you think about
what you want to do with your newfound fortune. After a few moments, you decide that if
you’re paid $250, then you’ll by a TV. If you’re paid less, you think, you’ll buy a radio instead.

This kind of test lends itself well to an
If statement. Let’s rewrite this scenario into a more
program-like format.
If your pay is equal to $250
Then Buy a TV
Else
Buy a Radio
EndIf
As you can see, the logic is very straightforward and translates well from English into
pseudo code. I used bold text to identify portions of the example to point out the key
VBScript language programming components that are
involved. I’ll go into greater detail about what each of
these keywords means a little later in the chapter.
Back to our scenario: Perhaps after thinking about it a
few more minutes, you decide that there are a number
of things that you might do with your pay, depending
on how much money you receive. In this case, you can
use the VBScript
Select Case statement to outline the
logic of your decisions in pseudo code format.
Definition
Pseudo code is a rough, English-like
outline or sketch of a script. By
writing out the steps you think will
be required to write a script in
pseudo code, you provide yourself
with an initial first-level script
design that will serve as a basis for
building the final product.
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Microsoft WSH and VBScript Programming for the Absolute Beginner, Second Edition
Select Case Your Pay
Case If you get $250 you’ll buy a TV
Case If you get $200 you’ll buy a VCR
Case If you get $100 you’ll buy a radio
Case Else You’ll just buy lunch
End Select
Again, I have used bold text to identify portions of the example to point out key VBScript
language programming components involved. In the next two sections of this chapter, I’ll
break down the components of the
If and Select Case statements into greater detail and
show you exactly how they work.
The If Statement
The VBScript If statement lets you test two values or conditions and alter the execution of
the script based on the results of the test. The syntax of this statement is as follows:
If condition Then
statements
ElseIf condition-n Then
statements
.
.
.
Else
statements
End If
Working with the If Statement
The If statement begins with the If keyword and ends with End If. condition represents the
comparison being performed. For example, you might want to see whether the value of
X is
equal to

250, like this:
If X = 250 Then
The keyword Then identifies the beginning of a list of one or more statements. statements is
a placeholder representing the location where you would supply whatever script statements
you want executed. For example, the following example displays a complete
If statement
that tests to see whether a variable has a value of 250, and if it does (that is, the test provides
equal to true), a message is displayed:
If X = 250 Then
WScript.Echo “Go and by that TV!”
End If
You may add as many statements as you want between the Then and End If keywords.
If X = 250 Then
WScript.Echo “Go and buy that TV!”
WScript.Echo “Buy a TV Guide while you are at it.”
WScript.Echo “And do not forget to say thank you.”
End If
But what happens if the tested condition proves false? Well, in the previous test, nothing.
However, by adding the
Else keyword and one or more additional statements, the script is
provided with an additional execution path.
If X = 250 Then
WScript.Echo “Go and buy that TV!”
WScript.Echo “Buy a TV Guide while you are at it.”
WScript.Echo “And do not forget to say thank you.”
Else
WScript.Echo “OK. Just purchase the radio for today.”
End If
Figure 5.5 provides a flowchart view of the logic used in this example.
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Chapter 5 • Conditional Logic
Figure 5.5
A flowchart
outlining the
logic behind a
typical If
statement.