Learn to Program with Small Basic

1 ' AndDemo.sb
2 TextWindow.Write("Game level: ")
3 gameLevel = TextWindow.ReadNumber()
4
5 TextWindow.Write("Score.....: ")
6 score = TextWindow.ReadNumber()
7
8 If ((gameLevel = 1) And (score > 100)) Then
9 TextWindow.WriteLine("You get 200 bonus points!")
10 EndIf
Listing 9-3: The And operator
The statement inside the If block (line 9) is run only if gameLevel equals
1 and score is greater than 100. If either of these two conditions is false, the
entire condition is found false and Small Basic won’t run the WriteLine()
method on line 9.
You can perform the same check by replacing lines 8–10 with the following
nested If statements:
If (gameLevel = 1) Then
If (score > 100) Then
TextWindow.WriteLine("You get 200 bonus points!")
EndIf
EndIf
Do you see how the And operator is a more concise way to test multiple
conditions? The nested If statements require five lines of code, but using
And, you can do the same thing in only three lines of code!
The Or Operator
How do you like your pizza? You might want to eat pizza only if it has four
kinds of meat or if the crust is gooey. When you have multiple conditions
but only one condition needs to be true, the Or operator comes into play.
Take a look at the truth table for the Or operator in Table 9-3.
Table 9-3: Truth Table for the Or Operator
If X is If Y is Then (X Or Y) is
"True" "True" "True"
"True" "False" "True"
"False" "True" "True"
"False" "False" "False"
If either of the two operands is true, or if they’re both true, the combined
logical expression is true. The logical expression is false only when
both operands are false.
118 Chapter 9