Compare 2 text files

We will read strings from each file while each of files has a data.

And we will compare each string from the first file with corresponding string from the second file.

All differences we will write in a memo.

procedure TForm1.Button1Click(Sender: TObject);

var

First, Second: TextFile;

Str, Str2: string;

begin

Memo1.Clear;

if (Edit1.Text<>'')and(Edit2.Text<>'') then

begin

AssignFile(First, Edit1.Text);

AssignFile(Second, Edit2.Text);

Reset(First);

Reset(Second);

while not EOF(First) do

begin

if EOF(Second)=True then

begin

Memo1.Lines.Add('*** ATTENTION ***');

Memo1.Lines.Add('SECOND file has finished

but FIRST file has had a data yet.');

Break;

end;

Readln(First, Str);

Readln(Second, Str2);

if CompareStr(Str, Str2)<>0 then

begin

Memo1.Lines.Add('FIRST - '+Str);

Memo1.Lines.Add('SECOND - '+Str2);

Memo1.Lines.Add(' ');

end;

end;

if EOF(Second)=False then

begin

Memo1.Lines.Add('*** ATTENTION ***');

Memo1.Lines.Add('FIRST file has finished

but SECOND file has had a data yet.');

end;

CloseFile(First);

CloseFile(Second);

if Memo1.Lines.Count=0 then

Memo1.Lines.Add('FIRST file is identical to SECOND file');

end;

end;