Paste: Rot13

with Ada.Text_IO; use Ada.Text_IO;

procedure Rot13 is
   C : Character;

begin
   while not End_Of_File(Standard_Input) loop
      Get(C);
      if (C >= 'A' and C <= 'M') or (C >= 'a' and C <= 'm') then
         C := Character'Val(Character'Pos(C) + 13);
      elsif (C >= 'N' and C <= 'Z') or (C >= 'n' and C <= 'z') then
         C := Character'Val(Character'Pos(C) - 13);
      end if;
      Put(C);
   end loop;
end;