MATLAB Programming

9 Classes and Objects
Example — A Polynomial Class
This example implements a MATLAB data type for polynomials by defining
a new class called polynom. The class definition specifies a structure for
data storage and defines a directory (@polynom) of methods that operate on
polynom objects.
This section covers
• “Polynom Data Structure” on page 9-26
• “Polynom Methods” on page 9-26
• “The Polynom Constructor Method” on page 9-27
• “Converter Methods for the Polynom Class” on page 9-28
• “The Polynom display Method” on page 9-30
• “The Polynom subsref Method” on page 9-31
• “Overloading Arithmetic Operators for polynom” on page 9-32
• “Overloading Functions for the Polynom Class” on page 9-34
• “Listing Class Methods” on page 9-36
Polynom Data Structure
The polynom class represents a polynomial with a row vector containing
the coefficients of powers of the variable, in decreasing order. Therefore,
a polynom object p is a structure with a single field, p.c, containingthe
coefficients. This field is accessible only within the methods in the @polynom
directory.
Polynom Methods
To create a class that is well behaved within the MATLAB environment and
provides useful functionality for a polynomial data type, the polynom class
implements the following methods:
• A constructor method polynom.m
• A polynom to double converter
9-26