MATLAB Object-Oriented Programming

Determining Equality of Objects

Equality for value objects means that the objects are of the same class and have the same

state.

Equality for handle objects means that the handle variables refer to the same object. You

also can identify handle variables that refer to different objects of the same class that

have the same state.

Equality of Value Objects

To determine if value objects are the same size and their contents are of equal value, use

isequal. For example, use the previously defined NumValue class to create two

instances and test for equality:

a = NumValue;

b = NumValue;

isequal(a,b)

ans =

1

a and b are independent and therefore are not the same object. However each represents

the same value.

If you change the value represented by a value object, the objects are no longer equal.

a = NumValue;

b = NumValue;

b.Number = 7;

isequal(a,b)

ans =

0

Value classes do not have a default eq method to implement the == operation.

Equality of Handle Objects

Handle objects inherit an eq method from the handle base class. You can use == and

isequal to test for two different relationships among handle objects:

7 Value or Handle Class — Which to Use