Problem mit Vorwärtsdeklaration

[fwsp]

Hallo,

ich bekomme es nicht hin eine function vorwärts zu deklarieren. kann mir jemand helfen und mir zeigen wo die vorwärtsdeklaration hin muss?

Delphi-Quellcode:

program PT_HUE_4_1;

{$APPTYPE CONSOLE}

uses
  SysUtils;

const
  Digits = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9'];
  Operators = ['+', '-', '*', '/', '~'];
  Neg = '~';

var
  PolTerm, AlgTerm: string;

function Negat(s: string): string;
begin
  if (s[1] = Neg) and (Length(s) = 2) then
  begin
    Result := '(-' + s[2] + ')';
  end;
end;

function Add(s: string): string;
begin
  if (s[2] in Digits) then
  begin
    //Result := s[2] + '+' + MakeAlg(MyCopy(s, 3, (Length(s) - 3)));
  end
  else if (s[2] in Operators) then
  begin
    //Result := MyCopy(s, )
  end;
end;

function Sub(s: string): string;
begin
  Result := s[2] + '-' + s[3];
end;

function Mult(s: string): string;
begin
  Result := s[2] + '*' + s[3];
end;

function Divi(s: string): string;
begin
  Result := s[2] + '/' + s[3];
end;

function MyCopy(s: string; Index, Length: Integer): string;
var
  i: Integer;
begin
  Result := '';
  for i := Index to Length do
  begin
    Result := Result + s[i];
  end;
end;

function MyTrim(s: string): string;
var
  i: Integer;
begin
  Result := '';
  for i := 1 to Length(s) do
  begin
    if (s[i] <> ' ') then
    begin
      Result := Result + s[i];
    end;
  end;
end;

function MakeAlg(s: string): string;
begin
  if (s[1] in Digits) then
  begin
    Result := s[1];
    Exit;
  end;

  case s[1] of
    '+':  Result := Add(s);
    '-':  Result := Sub(s);
    '*':  Result := Mult(s);
    '/':  Result := Divi(s);
  end;
end;

begin
  Writeln('Geben Sie den Term in polnischer Notation ein!');
  Readln(PolTerm);
  PolTerm := MyTrim(PolTerm);
  if (PolTerm <> '') then
  begin
    AlgTerm := MakeAlg(PolTerm);
    Writeln(AlgTerm);
  end;
  Readln;
  Readln;
  Readln;
end.