EOF when reading from a text file

atankersley

In this code InputFile and OutputFile are both text files in notepad. I added the word "QUIT" to the end of the InputFile to stop execution when there were no more records(Item Numbers) and it works. Is there a better way to do this? I normally use EOF as a Boolean with other languages but could not find it referenced anywhere.

IF InputFile.OPEN(FileNameIn) THEN
  BEGIN
    InputFile.READ(TNumber);
    WHILE TNumber <> 'QUIT' DO
      BEGIN
        ProgWin.UPDATE;
        MyItem.SETFILTER("No.",TNumber);
        IF (MyItem.FIND('-') = TRUE) THEN
          BEGIN
            OutputLine := MyItem."No." + '~' +
            FORMAT(MyItem."Unit Price");
            OutputFile.WRITE(OutputLine);
            Number := Number + 1;
            InputFile.READ(TNumber);
          END
        ELSE
          ERROR(NoItemNumber, TNumber);
     END;
  END
ELSE
  ERROR(NoFile, FileNameIn);

ara3n

You need to create an instream

  MyFile.OPEN(FileName);
  MyFile.CREATEINSTREAM(IStream);
  REPEAT
    IStream.READTEXT(textLine);   
  UNTIL IStream.EOS;

Marije_Brummel

I think

File.pos = file.len

Also works

But I like the streams.

kriki

Mark Brummel wrote:

I think

File.pos = file.len

Also works

But I like the streams.

But don't use this in a loop.
The File.POS and File.LEN are very slow!
So it is better to calculate the POS manually.
But of course: streams are an good alternative.

kine

From on-line help:

Read] := File.READ(Variable)
Read

Data type: integer

This optional return value tells you the number of bytes read.

File

Data type: file

Use this variable to refer to the file.

Variable

Data type: any

The destination variable.

It means, if you test the result of the reading and the result is =0 it means, there are no more data to read (you are on the end of file).

Common construction:

  ...
  While File.Read(Data) <> 0 do begin
     ...
  end;

ara3n

That not totally true. If you have file.textmode (true) read will return zero if the line is empty.

Also the way he has written the code he is not settng this property. So
InputFile.READ(TNumber) will read the whole file. the first time and will have an overflow error.

kine

Ah, sorry, you are right... :-#