Re: Assistance using classes

"Alf P. Steinbach" <>
Sun, 02 Jul 2006 20:13:45 +0200
* Daniel T.:

In article <>,
 "Alf P. Steinbach" <> wrote:

This is the code. Thsnks in advance

#include <string> // class Invoice uses C++ standard string class
using std::string;

// Invoice class definition
class Invoice
   Invoice( string, string, int, int ); // initializing constructors
   void setPartNumber(); // function that sets the part number
   string getPartNumber(); // function that gets the part number
   void setPartDescription(); // function that sets the part description
   string getPartDescription(); // function that gets the part description
   void setQuantity(); // function that sets the quantity
   int getQuantity(); // function that gets the quantity
   void setPrice(); // function that sets the price
   int getPrice(); // function that gets the price
   int getInvoiceAmount(); // function that calculates the invoice amount
   string number;
   string description;
   int quantity;
   int price;
}; // end class Invoice

This is technically a class, but the only C++ class feature it uses to
advantage is the constructor.

The rest, with setters and getters, is, with one exception, and assuming
you fix the lack of arguments in your setter functions, effectively as
if you'd just done:

   struct Invoice
       Invoice( string, string, int, int );
       string number;
       string description;
       int quantity;
       int price;

The exception is that simpler version allows referring to data in a
'const' object, whereas your more complicated version doesn't allow that.

At this stage in your education I recommend using the simpler version,
so as not being deluded that the code represents anything class-like:
it's just a collection of data with an initialization helper (the

Although the merit of his class may be at question, equating it with the
struct you show is not correct.

It is correct, in the context indicated.

His class could be re-implemented to
store all data in a database without any other code needing to be
changed for example, while your struct doesn't have that property.

Yes, that's possible in some /other/ context, such as an experienced
programmer; however, when even the syntax is a problem, the likelihood
of a database backend being added is negligible, and the machinery that
allows is that is only an impediment.

A: Because it messes up the order in which people normally read text.
Q: Why is it such a bad thing?
A: Top-posting.
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