with ada.text_io; -- context clause
with ada.integer_text_io; -- context clause

procedure using_files is -- procedure header (no parameters)

 -- declarations
 input_file_name : String (1..80);
 output_file_name : String (1..80);
 blank_string : constant String (1..80) := (others => ' ');

 input_file : ada.text_io.file_type;
 output_file : ada.text_io.file_type;
 last_in : integer;
 last_out : integer;
 temp_num : integer;
 square_num: integer;

begin -- procedure
   input_file_name := blank_string;
   output_file_name := blank_string;
   temp_num := 0;
		 
   ada.text_io.put("Enter input file name."); -- prompt
   ada.text_io.get_line(input_file_name, last_in);

        --Input file has to exist or Ada will throw an exception.
   ada.text_io.open(file => input_file,
                    mode=> ada.text_io.in_file,
                    name => input_file_name(1..last_in));
   ada.text_io.put (" INPUT file successfully opened "); -- debugging statement
   ada.text_io.new_line;  
 		 
		 
   ada.text_io.put("Enter output file name."); -- prompt
   ada.text_io.get_line(output_file_name, last_out);
   ada.text_io.put (" you entered "); -- echo of input
	ada.text_io.put_line (output_file_name);
    
   -- Output file does not have to exist - will be created
   ada.text_io.create(file => output_file,
                      mode => ada.text_io.out_file,
                      name => output_file_name(1..last_out));
   ada.text_io.put (" OUTPUT file successfully created ");

   -- put a heading in the output file
	ada.text_io.put_line (output_file, " Number      Square");
			
   --Read the five integers from the file.
   for i in 1..5 loop
     ada.integer_text_io.get(file => input_file, item => temp_num); -- named parameters
     square_num := temp_num * temp_num;
     ada.integer_text_io.put(file => output_file, item => temp_num, width => 6);
	  ada.integer_text_io.put (file => output_file, item => square_num, width => 12);
     ada.text_io.new_line(file =>output_file);
   end loop;
    
			 
   ada.text_io.close(file => input_file); -- closes input file
   ada.text_io.close(file => output_file); -- closes output file

   -- remind user where data came from and went to:input and output file names		  
  ada.text_io.put (" input came from "); 
  ada.text_io.put_line (input_file_name);
  ada.text_io.put (" output can be found in ");
  ada.text_io.put_line (output_file_name);
end using_files;