uses crt;
type
   nodetype=^node;
   node=record
      parem:nodetype;
      vasak:nodetype;
      nimi:string;
   end;
var
   first_node:nodetype;
   olemas:boolean;

//rekursiivne funktsioon puule solme lisamiseks, tagastab juure aadressi.
function lisa(pointer:nodetype; info:string):nodetype;
begin
if pointer=NIL then
   begin
   new(pointer);
   pointer^.parem:=NIL;
   pointer^.vasak:=NIL;
   pointer^.nimi:=info;
   end
else
   begin
      if pointer^.nimi<info then
         begin
         pointer^.parem:=lisa(pointer^.parem,info);
         end;
      if pointer^.nimi>info then
         begin
         pointer^.vasak:=lisa(pointer^.vasak,info);
         end;
   end;
   lisa:=pointer;
end;

//rekursiivne funktsioon nimede kuvamiseks t„hestikulises j„rjekorras.
procedure inorder(pointer:nodetype);
begin
if pointer^.vasak<>NIL then inorder(pointer^.vasak);
writeln(pointer^.nimi);
if pointer^.parem<>NIL then inorder(pointer^.parem);
end;

//rekursiivne protseduur, mis nime olemasolul annab globaalsele muutujale
//olemas v„„rtuse true;
procedure otsi(pointer:nodetype; info:string);
begin
   if (pointer^.nimi<info) AND (pointer^.parem<>NIL) then otsi(pointer^.parem,info);
   if pointer^.nimi=info then olemas:=true;
   if (pointer^.nimi>info) AND (pointer^.vasak<>NIL) then otsi(pointer^.vasak,info);
end;

procedure menu;
var
key:char;
name:string;
begin
repeat
repeat
clrscr;
writeln(' VALI TEGEVUS ');
writeln('---------------');
writeln('(L)isa nimi');
writeln('(O)tsi nime');
writeln('(T)rki nimed');
writeln('(V)„lju');
writeln();
key:=readkey;
until key in ['L','l','O','o','T','t','V','v'];
case key of
    'L','l':
            begin
            write('Sisesta nimi: ');
            readln(name);
            first_node:=lisa(first_node,name);
            textcolor(green);
            writeln('Lisatud!');
            readkey;
            normvideo;
            end;
    'O','o':
            begin
            write('Sisesta nimi: ');
            readln(name);
            otsi(first_node,name);
            if olemas=true then
                begin
                textcolor(green);
                writeln('Nimi ',name,' on olemas!');
                normvideo;
                end
            else
                begin
                textcolor(red);
                writeln('Nimi ',name,' puudub!');
                normvideo;
                end;
            olemas:=false;
            readkey;
            end;
    'T','t':
            begin
            textcolor(green);
            clrscr;
            writeln('Nimed t„hestikulises j„rjekorras: ');
            writeln('----------------------------------');
            normvideo;
            inorder(first_node);
            readkey;
            end;
end; //case
until (key='v') or (key='V');
end;

begin
first_node:=NIL;
olemas:=false;
menu;
end.