WITH Ada.Text_IO;
WITH Simple_Dates;
PACKAGE
Compact IS
------------------------------------------------------------------
--| This package provides data structures and operations for
--| manipulating a simple "data base" of audio compact
discs, each
--| record containing a code number, artist, disc title, category
--| of disc, date of purchase, and price you paid.
--|
--| The package makes use of resources provided
--| by the package Simple_Dates.
--|
--| Author: Michael B. Feldman, The George Washington University
--| Last Modified: March 1997
------------------------------------------------------------------
-- constant and type
definitions
NameSize: CONSTANT Positive :=10;
MaxDiscs:
CONSTANT Positive := 25;
SUBTYPE BarCode IS
Positive RANGE
00001..99999;
SUBTYPE NameType IS
String(1..NameSize);
SUBTYPE PriceType IS
Float
RANGE 0.00 ..
99.99;
TYPE Categories IS (Jazz, Rock,
Classical, Comedy);
TYPE Disc IS
PRIVATE;
--
operations
-- START
NEW
PROCEDURE Get(Item: OUT Disc; File:
IN Ada.Text_IO.File_Type);
-- Pre: File exists and is open for
reading
-- Post:
Get a disc record from a file
PROCEDURE Put(Item: IN Disc;
File: IN Ada.Text_IO.File_Type);
-- Pre: Item is defined, file exists and is
open for writing
--
Post: Writes the disc record to the
file
-- END
NEW
PROCEDURE Get (Item: OUT
Disc);
-- Pre: None
-- Post: Gets a disc record,
robustly, from the keyboard
PROCEDURE Put (Item: IN
Disc);
-- Pre: Item is defined
-- Post: Displays one disc record
on the screen
PROCEDURE
DisplayDatabase;
--
Pre: The database has at least
been cleared
--
Post: Displays the entire database on the
screen
PROCEDURE
ClearDatabase;
--
Pre: None
-- Post: The database behaves as
though it is empty
PROCEDURE
ReadDatabase;
--
Pre: None
-- Post: Reads all records from a
file into the database
PROCEDURE
WriteDatabase;
--
Pre: The database has at least
been cleared
--
Post: Writes all records in the database to a file
PROCEDURE FindDisc(Code: IN
BarCode;
Item: OUT Disc; Success: OUT Boolean);
-- Pre: Code is defined
-- Post: If this disc is already in
the database, returns the
--
disc record and Success is True;
--
otherwise, Success is
False
PROCEDURE AddDisc (Item: IN Disc;
Success: OUT Boolean);
-- Pre: Item is
defined
-- Post: If
this disc is not already in the database, adds this
--
disc to the database and Success is True;
--
otherwise, Success is
False
PROCEDURE DeleteDisc (Code: IN
BarCode; Success: OUT Boolean);
-- Pre: Tag is defined
-- Post: If this disc is already in
the database, deletes this
--
disc from the database and Success is True;
--
otherwise, Success is
False
PRIVATE
TYPE Disc IS RECORD
CodeNumber:
BarCode;
Artist:
NameType;
Title:
NameType;
Category:
Categories;
PurchaseDate:
Simple_Dates.Date;
PurchasePrice: PriceType;
END
RECORD;
END Compact;