Well testing other routines in my dxutil suite, I decided to evalute common implementation of for loops.

    Download for1.pas source

Uses
   dxutil_environment;// contains TimeCounter for Windows, Linux and Mac

Var
   Loop:LongWord;
   StartTime:Comp;
   S,Result:AnsiString;
   Loop2:Longint;

Begin
   S:='AbCdEfGhIjKlMnOpQrStUvWxYz';
   Writeln('Uppercase()');
   StartTime:=Trunc(TimeCounter);
   For Loop:=1 to 100000000 do begin
      Result:=S;
      for Loop2 := 1 to Length(Result) do
         if Result[Loop2] in ['a'..'z'] then Dec(Result[Loop2], 32);
   end;
   System.Write('Up ',Trunc(Trunc(TimeCounter)-StartTime));
   StartTime:=Trunc(TimeCounter);
   For Loop:=1 to 100000000 do begin
      Result:=S;
      for Loop2 := Length(Result) downto 1 do
         if Result[Loop2] in ['a'..'z'] then Dec(Result[Loop2], 32);
   end;
   System.Writeln(' DownTo ',Trunc(Trunc(TimeCounter)-StartTime));
end.

     The results, Up 25021 DownTo 24069... the downto is 1000ms faster (over 100 million calls). Mostly likely due to the Length of Result is not being evaluated for Loop2 like it is for the way people normally write these types of loops.

G.E. Ozz Nixon Jr.

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