Important statements in reading .txt

[asdf]

assignfile(dottxt,eFilenameEdit.Text);
try                           // 1
reset(dottxt);          // 2
  repeat
  readln(dottxt,ln);
  until(eof(dottxt)) ;
finally                      //3
closefile(dottxt);
end;                       // try-finally
end;       

Why without 1, 2 or 3 program has errors?

[Yogi]

You are simply reading past eof

Try this:

assignfile(dottxt,eFilenameEdit.Text);
reset(dottxt);         
while not eof(dottxt) do
  readln(dottxt,ln);
closefile(dottxt);
end;       

[Mando]

Hi.

2 is mandatory to read file. It opens the file in read mode.

if you put it, 1 and 3 are unnecessary,
unless the file does not exist. But you can check if file exists with this

Code: [Select]


if fileExists(eFilenameEdit.Text) then
begin
  assignfile(dottxt,eFilenameEdit.Text);

  reset(dottxt);         
  repeat
    readln(dottxt,ln);
  until(eof(dottxt)) ;

  closefile(dottxt);
end else showMessage('File '+eFilenameEdit.Text+' doesn`t exist');       




[Yogi]

Hi

Your code also will give an error if the file exists but is empty

Therefore you should not use "repeat until eof". Better to use "while not eof" so
eof is checked before the readln

[Mando]

HI:

With delphi maybe. But in lazarus SVN: 273258 works fine.


regards.

Try attached project.

[asdf]

Thank you so much, Yogi and Mando  .