Question

OVERVIEW: The purpose of this assignment is to reinforce Ada concepts.

• Specifically, the assignment is to construct a Book class where a book contains the following:
  • an author
  • a title
  • a number of pages
• You also need a “main program” to create a book and then display its contents.
• Have it allow the user to change the values.

Answer 1

CODING :

books.adb

with Ada.Characters.Handling;
use Ada.Characters.Handling;

package body Books is

-----------------
-- create_book --
-----------------

function create_book
(author: in String;
title: in String;
leaves: in PAGES)
return Book
is
boo : Book;
begin
if author'Length > MAX_AUTHOR_NAME_SIZE then
boo.author := author(1 .. MAX_AUTHOR_NAME_SIZE);
else
boo.author (1 .. author'Length) := author;
end if;
if title'Length > MAX_TITLE_SIZE then
boo.title := title(1 .. MAX_TITLE_SIZE);
else
boo.title (1 .. title'Length) := title;
end if;

boo.leaves := leaves;
return boo;
end create_book;

----------------
-- get_author --
----------------

function get_author (s: in Book) return String is
begin
return s.author;
end get_author;

---------------
-- get_title --
---------------

function get_title (s: in Book) return String is
begin
return s.title;
end get_title;

---------------
-- get_pages --
---------------

function get_pages (s: in Book) return PAGES is
begin
return s.leaves;
end get_pages;

end Books;
books.ads

package Books is

type Book is private;

MAX_AUTHOR_NAME_SIZE: constant Positive := 30;

MAX_TITLE_SIZE: constant Positive := 100;

MAX_PAGES_SIZE: constant Positive := 10000;

type PAGES is new Positive range 1 .. MAX_PAGES_SIZE;

function create_book (author: in String; title: in String; leaves: in PAGES)
return Book
with pre => author'Length > 0 and title'Length > 0;

function get_author (s: in Book) return String;

function get_title (s: in Book) return String;

function get_pages (s: in Book) return PAGES;

private
type Book is
record
author: String (1 .. MAX_AUTHOR_NAME_SIZE) := (others => ' ');
title: String (1 .. MAX_TITLE_SIZE) := (others => ' ');
leaves: PAGES;
end record;

end Books;
test_book.adb

with Books, Ada.Text_IO;
use Books, Ada.Text_IO;

procedure Test_Book is

boo: Book;

procedure display_book (s: in Book) is

begin
put ("Author: ");
put_line (get_author (s));
put ("Title: ");
put_line (get_title (s));
put ("Pages: ");
put_line (Positive'Image (Positive(get_pages(s))));
end display_book;

begin
boo :=create_book("Hu","The life of me",150);
display_book(boo);
end Test_Book;

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