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60 lines
1.5 KiB
Markdown
60 lines
1.5 KiB
Markdown
The WHILE...WEND statement is used to repeat a block of statements while the condition is met.
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## Syntax
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> WHILE condition
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> .
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> .
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> .
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> WEND
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## Description
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* condition is a numeric expression used to determine if the loop will execute.
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* statements will execute repeatedly while condition is a non-zero value.
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* [EXIT WHILE](EXIT-WHILE) can be used for emergency exits from the loop.
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* Use [_CONTINUE](_CONTINUE) to skip the remaining lines in the iteration without leaving the loop.
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* A [DO...LOOP](DO...LOOP) can use the same DO WHILE condition to get the same results.
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* WHILE loops only run if the WHILE condition is True.
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**Relational Operators:**
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| Symbol | Condition | Example Usage |
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| -- | -- | -- |
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| = | Equal | IF a = b THEN |
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| <> | NOT equal | IF a <> b THEN |
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| < | Less than | IF a < b THEN |
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| > | Greater than | IF a > b THEN |
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| <= | Less than or equal | IF a <= b THEN |
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| >= | Greater than or equal | IF a >= b THEN |
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## Example(s)
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Reading an entire file. Example assumes the program has a [OPEN](OPEN) as #1
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```vb
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OPEN "Readme.txt" FOR INPUT AS #1
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WHILE NOT EOF(1)
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_LIMIT 1 'limit line prints to one per second
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LINE INPUT #1, text$
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IF INKEY$ = CHR$(27) THEN EXIT WHILE 'ESC key exits
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PRINT text$
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WEND
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```
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Clearing the keyboard buffer.
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```vb
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WHILE INKEY$ <> "" : WEND
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```
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## See Also
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* [DO...LOOP](DO...LOOP)
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* [FOR...NEXT](FOR...NEXT)
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* [UNTIL](UNTIL) (condition)
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* [_CONTINUE](_CONTINUE)
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