I need to pad an integer with zeros.... do I,

A) Use the in built functionality in Delphi (Format('%.6d', [ 1234 ]) = '001234')

or 

B) Write my own using string concatenation!

function PadInteger(AValue, ASize: Cardinal; APad: Char): String;
var
  StringIndex: Integer;
  StrLength: Integer;
begin
  Result := IntToStr(AValue);
  StrLength := Length(Result);
  if StrLength < Integer(ASize) then
  begin
    for StringIndex := StrLength to ASize-1 do
      Result := APad+ Result;
  end
end;

if you answered B 

YOU ARE CORRECT

YOU WIN A PUNCH IN THE FACE