Append one file to other

You may copy contents of a first file to [new.$] file. After that, you may add contents of a second file to [new.$] and then delete first file and rename [new.$] file to name of the first file.

procedure TForm1.Button3Click(Sender: TObject);

var

Str: string;

F1, F2, F3: TextFile;

begin

Label3.Caption:='Processing...';

AssignFile(F1, Edit1.Text);

AssignFile(F2, Edit2.Text);

AssignFile(F3, 'new.$');

Reset(F1);

Reset(F2);

Rewrite(F3);

while not(EOF(F1)) do

begin

Readln(F1, Str);

Writeln(F3, Str);

end;

while not(EOF(F2)) do

begin

Readln(F2, Str);

Writeln(F3, Str);

end;

CloseFile(F1);

CloseFile(F2);

CloseFile(F3);

DeleteFile(ExtractFileName(Edit1.Text));

RenameFile('new.$', ExtractFileName(Edit1.Text));

DeleteFile('new.$');

Label3.Caption:='Processing done';

end;