with ada.containers.Generic_Array_Sort;
with ada.containers.Generic_Constrained_Array_Sort;
with Ada.Text_IO; use Ada.Text_IO;
with Ada.Integer_Text_IO; use Ada.Integer_Text_IO;

procedure gsort is
    type individual is record a, b: natural; end record;

    function "<"(l, r: individual) return boolean is (l.b < r.b); 
    function gt(l, r: individual) return boolean is (l.a > r.a); 

    subtype pop_range is natural range 1 .. 10;

    -- CONSTRAINED TYPE
    type population is array(pop_range) of individual;

    procedure c_sort is new ada.containers.Generic_Constrained_Array_Sort(
        Index_Type => pop_range  
       ,Element_Type => individual 
       ,Array_Type => population
       -- ,"<" => gt
       -- -- Default value for the param "<" is:
       -- -- any existing function named "<" of the correct type
       );


    -- UNCONSTRAINED TYPE
    type upopulation is array(pop_range range <>) of individual;

    procedure u_sort is new ada.containers.Generic_Array_Sort(
         index_type => pop_range 
        ,array_type => upopulation 
        ,element_type=>individual
        );
         --  By default, uses the above function < for individuals


    procedure put(pop: population) is
    begin
      for p of pop loop
          put(p.a);
          put(p.b);
          new_line;
      end loop;
    end put;



    pop: population ;-- := (others => (0, 0));
begin
    
    put(pop);
    c_sort(pop); 
    new_line;
    put_line("after sorting");
    put(pop);

end gsort;