Nested functions/procedures in Ada, and count unique according to a certain idea of equality.

counter.ads

package Counting is
   type Element is 
      record
         S  : String (1 .. 3);
         E1 : Integer;
         E2 : Integer;
      end record;
   
   type Elements is array (Positive range <>) of Element;
   
   function Count_Unique (S : Elements) return Integer;
end Counting;

counting.adb

package body Counting is
   
   function Count_Unique (S : Elements) return Integer
   is
      Found : Boolean;
      C     : Integer := 0;
      
      function Compare (I, J : Integer) return Integer
      is
      begin
         if S(I).E2 = S(J).E2 then
            return 0;
         elsif S(I).E1 /= S(J).E1 then
            return S(J).E1 - S(I).E1;
         else
            return S(J).E2 - S(I).E2;
         end if;
      end;
      
   begin
      for I in S'Range loop
         Found := False;
         for J in S'First .. I - 1 loop
            if Compare(I, J) = 0 then
               Found := True;
               exit;
            end if;
         end loop;
         if not Found then
            C := C + 1;
         end if;
      end loop;
      return C;
   end Count_Unique;
   
end Counting;

ctest.adb

with Ada.Text_IO; use Ada.Text_IO;
with Ada.Integer_Text_IO; use Ada.Integer_Text_IO;
with Counting; use Counting;

procedure CTest is
   S : Elements := (
                    ("zak", 2, 0),
                    ("mac", 3, 1),
                    ("abc", 4, 2),
                    ("zak", 5, 0)
                   );
begin
   Put (Count_Unique (S));
   New_Line;
end CTest;