初学者的一个问题，请帮忙！

Question

procedure Tform1.finddialog1find(sender:Tobject);
var
  foundat:longint;
  startpos,toend:integer;
begin
  with richedit1 do
  begin
    if sellength<>0 then
      startpos:=selstart+sellength
    else
      startpos:=0; 
    toend:=length(text)-startpos;
                               ~~
    foundat:=findtext(finddialog1.findtext,startpos,toend,[stmatchcase]);
    if foundat<>-1 then
    begin
      setfocus;
      selstart:=foundat;
      sellength:=length(finddialog1.findtext);
    end;
  end;
end;

Answer 1

总提示 foundat:=findtext(finddialog1.findtext,sytartpos,toend,[stmatchcase]);这句话有错。

Answer 2

"foundat:=findtext"这句后面停住了，提示undeclared indentifier:'findtext'还有undeclared identifier:'stmatchcase'这两个错误