Сформировать бинарное дерево, которое отражает служебные слова языка Паскаль

const
  ServW : array[1..9] of char = ('I','T','E','C','O','W','D','R','U');
type
  tData = Char;
  pNode = ^Node;
  Node  = record
    Data        : tData;
    Left, Right : pNode;
  end;
procedure AddToTree(var T:pNode; aData:tData);
begin
  if t=nil then begin
    New(T);
    T^.Data:=aData;
    T^.Left:=nil;
    T^.Right:=nil;
  end else if aData>T^.Data then AddToTree(T^.Right,aData)
  else AddToTree(T^.Left,aData);
end;
procedure WriteTr(T:pNode);
begin
  If T=nil then exit;
  WriteTr(T^.Left);
  write(T^.Data,' ');
  WriteTr(T^.Right);
end;
function Find(T:pNode;aData:TData) : pNode;
begin
  if T=nil then Find:=nil
  else if T^.Data=aData then Find:=T
  else if aData<T^.Data then Find:=Find(T^.Left,aData)
  else Find:=Find(T^.Right,aData);
end;
procedure Remov(var T,Prt:pNode;aData:tData);
var Prev,Ins,p:pNode;
begin
  if T=nil then exit
  else if aData<T^.Data then Remov(T^.Left,T,aData)
  else if aData>T^.Data then Remov(T^.Right,T,aData)
  else if (T^.Left=nil) and (T^.Right=nil) then begin
    dispose(T);
    T:=nil;
  end else if (T^.Left<>nil) and (T^.Right=nil) then begin
    Ins:=T;
    if Prt=nil then T:=T^.Left
    else if aData<Prt^.Data then Prt^.Left:=T^.Left
    else Prt^.Right:=T^.Left;
    dispose(Ins);
    Ins:=nil;
  end else if (T^.Left=nil) and (T^.Right<>nil) then begin
    Ins:=T;
    if Prt=nil then T:=T^.Right;
    if aData<Prt^.Data then Prt^.Left:=T^.Right
    else Prt^.Right:=T^.Right;
    dispose(Ins);
    Ins:=nil;
  end else begin
    p:=T;
    Ins:=T^.Right;
    while Ins^.Left<>nil do begin
      Prev:=Ins;
      Ins:=Ins^.Left;
    end;
    Prev^.Left:=Ins^.Right;
    Ins^.Right:=T^.Right;
    Ins^.Left:=T^.Left;
    if Prt=nil then T:=Ins
    else if aData<Prt^.Data then Prt^.Left:=Ins
    else Prt^.Right:=Ins;
    dispose(p);
    p:=nil;
  end;
end;
var
  T,p : pNode;
  i : integer;
begin
  T := nil;
  for i := 1 to 9 do AddToTree(T,ServW[i]);
  WriteTr(T);
  writeln;
  p:=nil;
  if Find(T,'O')<>nil then Remov(T,p,'O');
  WriteTr(T);
  writeln;
  if Find(T,'O')=nil then AddToTree(T,'O');
  WriteTr(T);
  readln;
end.

  if Find(T,'O')<>nil then Remov(T,p,'O') else AddToTree(T,'O');
  WriteTr(T);