programming-for-dummies

Creating Subprograms and Functions 601
The DO-UNTIL loop repeats until a certain condition becomes True. The
DO-WHILE loop repeats while a certain condition remains True. The two
variations of the DO-UNTIL loop look like this:
Book VI
Chapter 5
DO UNTIL condition
Command
Loop
In this version, the DO-UNTIL loop checks if a condition is True. If so, this
loop never runs. If not, this loop runs at least once. The second variation of
the DO-UNTIL loop looks like this:
Visual Basic and
REALbasic
DO
Command
Loop UNTIL condition
This loop runs at least once before checking a condition. If the condition is
True, the loop stops. The DO-WHILE loops work nearly identically. If you
want to make a loop that may run zero or more times, you’d use this DO-
WHILE loop:
DO WHILE condition
Command
Loop
If you want a DO-WHILE loop that runs at least once, you’d use this variation:
DO
Command
Loop WHILE condition
Although REALbasic lacks the DO-WHILE loop, it does offer a WHILE-WEND
loop, which looks like this:
WHILE condition
Command
WEND
Creating Subprograms and Functions
You can create a subprogram (or a procedure) by using the SUB keyword as
follows:
SUB Name (Parameter list)
Command
END SUB