generic
    type INDEX is range <>;
    type ITEM is private;
    with function "<"(Left,Right:ITEM) return Boolean is <>;
    type LIST is array (INDEX range <>) of ITEM;
-- given the above types and function this package defines the following
function SEARCH(The_table:LIST; TARGET:ITEM) return INDEX;
---------------------------------------------------------------
function SEARCH(The_table:LIST; TARGET:ITEM) return INDEX is
    NOT_FOUND:exception; --when search fails to find item
    type SUBLIST is array(INDEX range <>) of ITEM;
		--Binary search works by extracting sublists
    function SUB_SEARCH(The_subtable:SUBLIST) return INDEX is 
    begin
	if the_subtable'length<=1 then
		if the_subtable(the_subtable'first)= Target then 
			return The_subtable'first;
		else 	raise not_FOUND;
		end if;
	else
  	  declare MID:INDEX:=(the_subtable'First+The_subTable'LAST)/2;
	  begin
	    if the_subtable(mid)<target then
	         return sub_Search(The_subtable(Mid+1..The_subtable'last));
	    elsif Target<the_subtable(mid) then
	         return sub_search(The_subtable(the_subtable'first..Mid-1));
	    else -- the_subtable(mid)=Target then
		 return MID;
	    end if;
	  end;
 
	end if;
    end SUB_SEARCH;
begin
	return SUB_SEARCH(SUBLIST(The_TABLE(The_TABLE'FIRST..The_TABLE'LAST)));
end SEARCH;