program avltst;

{$I avlmod.typ}

var i,r : avlelement;
    u : avllink;
    op : char;

{$I avlmod.ext}

begin
while 5 < 10 do
   begin
   write ('m,i,s,d....');
   readln (op);
   case op of
	'm' : avlmakenull(u);
        'i' : begin
                 write('character... ');
                 readln (i);
                 avlinsert(i,u);
              end;
        's' : begin
                 write('character... ');
                 readln (i);
                 if avlsearch(i,r,u) then writeln(r) else writeln ('not');
              end;
       'd': avldump(u,output);
        end;
   end;
end.

.