MATLAB Object-Oriented Programming

Expression Evaluation in Handle and Value Classes

The following example shows how value and handle object behave when assigned to

properties as default values. Suppose that you have the following classes.

Expressions in Value Classes

The ClassExp class has a property that contains a ContClass object:

classdef ContClass

properties

% Assign current date and time

TimeProp = datestr(now)

end

end

classdef ClassExp

properties

ObjProp = ContClass

end

end

When you first use the ClassExp class, MATLAB creates an instance of the ContClass

class. MATLAB initializes both classes at this time. All instances of ClassExp include a

copy of this same instance of ContClass.

a = ClassExp;

a.ObjProp.TimeProp

ans =

08-Oct-2003 17:16:08

The TimeProp property of the ContClass object contains the date and time when

MATLAB initialized the class. Creating additional instances of the ClassExp class shows

that the date string has not changed:

b = ClassExp;

b.ObjProp.TimeProp

ans =

08-Oct-2003 17:16:08

6 Defining and Organizing Classes