Blitz 2000 - Programming: If...Then...Else...Endif decisions

If...Then...Else...Endif decisions

As mentioned in the introduction, If commands can be added to your code to make your program execute different code based on different values of expressions. It allows you to either execute one sequence of commands on occaision, or to select one of two possible sequences of commands. There are two basic forms that the command can take. The first is:

If Expression Then Command [ Else Command ]

In this case, if the value of the Expression evaluates to true, the command following the Then will be performed. However, if the expression evaluates to false, the command after the Else will be performed (if it is included - this part is optional).

age.w = 21 If age>40 Then NPrint "It's all downhill frm here ;)" Else NPrint "You have lots to look forward to - life begins at 40" MouseWait End

It is even possible to use more If statements in place of the commands which come after the Then or Else keywords.

The second style of using the If statement is as follows:

If Expression Command1 Command2 ... CommandN [Else AltCommand1 AltCommand2 ... AltCommandN ] EndIf

Notice there is no Then keyword in this mode. It is also possible to use "End If" (with a space). Similar to the first mode, if the value of the expression is true then the first set of commands will be performed. If the value of the expression is false, then the alternate set of commands are carried out. The Else keyword and alternate commands are optional again. Here is an example of using the If structure in the second way:

name$="John" If name$="Bob" NPrint "Hey Bob, bit of a doofus name, how's about we change it?" name$="Frank" NPrint "There, that's better." Else NPrint "That's a fine name." NPrint "(Well, maybe)" EndIf NPrint "And your fixed name is ",name$ MouseWait End

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