Programming 597
While...EndWhile Loops
A
While...EndWhile loop repeats a block of commands as long as a specified condition is
true. The syntax of the
While command is:
While condition
When While is executed, the condition is evaluated. If condition is true, the loop is
executed; otherwise, program control jumps to the command following
EndWhile.
Note: The While command does not automatically change the condition. You must
include commands that allow the program to exit the loop.
At the end of the loop (
EndWhile), program control jumps back to the While command,
where condition is re-evaluated.
To execute the loop the first time, the condition must initially be true.
• Any variables referenced in the condition must be set before the
While command.
(You can build the values into the program or prompt the user to enter the values.)
• The loop must contain commands that change the values in the condition, eventually
causing it to be false. Otherwise, the condition is always true and the program
cannot exit the loop (called an infinite loop).
x | 5
x < 5
:While x<5
: --------
: --------
:EndWhile
:--------
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