Show message if string not found in memo - string

Question

procedure TForm1.bFAT1Click(sender: TObject);
var
FAT: Integer;
begin
for FAT := 0 to memo1.lines.Count - 1 do
begin
if AnsiContainsStr(memo1.lines[FAT], 'Olive Oil') then
begin
ShowMessage('Olive Oil exist!');
end;
end;
// But how to show message if integer is empty?
end;
I want to do something if no line contains 'Olive Oil'. How to do it?

Answer 1

What you need is an Exit statement to leave the procedure as soon as you found a matching element. That way, when you reach the end of the procedure, you know that you have not found a matching element:
for FAT := 0 to memo1.lines.Count - 1 do
begin
if AnsiContainsStr(memo1.lines[FAT], 'Olive Oil') then
begin
ShowMessage('Olive Oil exist!')
Exit; // we can stop here since we found it
end;
end;
// we only come here if no line contained 'Olive Oil' (because of the EXIT)
ShowMessage('Olive Oil does not exist!');
Edit: (inspired by #David) It is good practice to separate your logic from the UI / display (for example ShowMessage). To do that you can define a function like this:
function IndexOfLineContaining(const Text : String; Lines : TStrings) : Integer;
begin
for Result := 0 to Lines.Count - 1 do
if AnsiContainsStr(Lines[Result], Text) then
Exit;
Result := -1;
end;
On top of that you could easily define a boolean function:
function HasLineContaining(const Text : String; Lines : TStrings) : Boolean;
begin
Result := (IndexOfLineContaining(Text, Lines) > -1);
end;
and use that to do your message display:
if HasLineContaining('Olive Oil', Memo1.Lines) then
ShowMessage ('foo')
else
ShowMessage ('bar');
I suggest that you work a bit on your terminology to make your questions clearer. An integer cannot be empty and the sentence " do something if [FAT] do not found 'Olive Oil'." with FAT being an integer does not make any sense.