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48 lines
2.2 KiB
Markdown
48 lines
2.2 KiB
Markdown
See [OPEN](OPEN).
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The **INPUT** file mode in an [OPEN](OPEN) statement opens an existing file for [INPUT (file statement)](INPUT-(file-statement)).
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## Syntax
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> [OPEN](OPEN) fileName$ FOR **INPUT** AS #filenumber%
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* If fileName$ does not exist, attempting to open it FOR INPUT will create a program [ERROR Codes](ERROR-Codes). Use [_FILEEXISTS](_FILEEXISTS) to avoid errors.
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* The file number can be determined automatically by using a [FREEFILE](FREEFILE) variable value.
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* Mode can use [INPUT (file statement)](INPUT-(file-statement)) #, [LINE INPUT (file statement)](LINE-INPUT-(file-statement)) # or [INPUT$](INPUT$) to read the file data.
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* Use the [EOF](EOF) function to avoid reading data past the end of a file and creating an [ERROR Codes](ERROR-Codes).
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* Input file statements will use the same file number as the OPEN statement.
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* The INPUT mode allows the same file to be opened in another mode with a different number.
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* **NOTE: [LINE INPUT (file statement)](LINE-INPUT-(file-statement)) will work faster in [BINARY](BINARY) than INPUT mode in QB64 to stay compatible with QBasic.**
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## Example(s)
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Avoiding an INPUT mode or [INPUT (file statement)](INPUT-(file-statement)) read error using a FileExist function. QB64 can use the [_FILEEXISTS](_FILEEXISTS) function.
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```vb
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DIM Fdata$(100)
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INPUT "Enter data file name: ", datafile$
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IF _FILEEXISTS(datafile$) THEN
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D% = FREEFILE: count = 0
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OPEN datafile$ FOR INPUT AS #D%
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DO UNTIL EOF(D%)
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count = count + 1
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LINE INPUT #D%, Fdata$(count)
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IF count = 100 THEN EXIT DO ' don't exceed array size!
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LOOP
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CLOSE #D%
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ELSE : PRINT "File not found!"
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END IF
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```
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> *Explanation:* The [_FILEEXISTS](_FILEEXISTS) function is used before `OPEN datafile$ FOR INPUT AS #D%`, which would generate an error in case the file didn't exist.
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## See Also
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* [INPUT (file statement)](INPUT-(file-statement)), [LINE INPUT (file statement)](LINE-INPUT-(file-statement)), [INPUT$](INPUT$) (file input)
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* [INPUT](INPUT), [LINE INPUT](LINE-INPUT), [INPUT$](INPUT$) (keyboard input)
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* [APPEND](APPEND), [RANDOM](RANDOM), [OUTPUT](OUTPUT), [BINARY](BINARY)
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* [READ](READ), [DATA](DATA)
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* [_FILEEXISTS](_FILEEXISTS), [_DIREXISTS](_DIREXISTS)
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