IF … THEN … ELSE

Programs make decisions with IF. The condition must be a Boolean — something that is True or False:

if iAge >= 17 then
  lblResult.Caption := 'You may apply!'
else
  lblResult.Caption := 'Not yet…';

Two rules that catch everyone at first:

• No semicolon before ELSE. The line above the else may not end with ;
• If a branch has more than one statement, wrap it in begin … end.

The comparison operators are =, <> (not equal), <, >, <= and >=.

Your task

In South Africa you may apply for a learner's licence at 17. Read an age and tell the user whether they can apply — and if not, exactly how many years they still have to wait.

procedure TfrmLicence.btnCheckClick(Sender: TObject);
var
  iAge : Integer;
begin
  iAge := StrToInt(edtAge.Text);
  if iAge >= 17 then
    lblResult.Caption := 'You may apply for a learner''s licence!'
  else
    lblResult.Caption := 'Only ' + IntToStr(17 - iAge) + ' more year(s) to go';
end;