Test case : Prime Numbers using Ada

                        
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-- Prime_List
-- Generate a list of prime numbers, the count of which is
-- entered from the command line.
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with Ada.Command_Line;
use Ada.Command_Line;
with Ada.Text_Io;
use Ada.Text_Io;
with Ada.Integer_Text_Io;
use Ada.Integer_Text_Io;
with Ada.Numerics.Generic_Elementary_Functions;
procedure Prime_List is 
   subtype Max_Range is Positive range 2..Positive'Last;
   
   function Is_Prime (Value : Positive ) return Boolean is
      package Math is new Ada.Numerics.Generic_Elementary_Functions(Float);
      use Math;
      Num    : Positive := 3;  
      Result : Boolean  := True;
      Limit  : constant Positive := Positive(sqrt(Float(Value)));
   begin
      loop
         if ((Value mod Num) = 0) and then Value /= Num then
            Result := False;
            exit;
         end if;
         exit when Num > Limit;
         Num := Num + 2;
      end loop;
      return Result;
   end Is_Prime;

   procedure Print (Count : Natural; Item  : Positive ) is 
   begin
      Put(Item  => Count, Width => 7);
      Put(" : ");
      Put(Item  => Item, Width => 10);
      New_Line;
   end Print;

   P1       : Positive  := 2;  
   Possible : Positive;  
   Count    : Natural   := 1;  
   Max      : Max_Range;  
begin
   Print(Count, P1);
   Possible := 3;
   Max := Max_Range'Value(Argument(1));
   while Count < Max loop
      if Is_Prime(Possible) then
         Count := Count + 1;
         Print(Count, Possible);
      end if;
      Possible := Possible + 2;
   end loop;
end Prime_List;