Main Content

Control Sequence of Constructor Calls

MATLAB® does not guarantee the sequence in which superclass constructors are called when constructing a subclass object. However, you can control this order by calling superclass constructors explicitly from the subclass constructor.

If you explicitly call a superclass constructor from the most specific subclass constructor (ClassC in the following diagram), then MATLAB calls the most specific subclass constructor first. If you do not make an explicit call to a superclass constructor from the subclass constructor, MATLAB makes the implicit call when accessing the object.

Suppose that you have a hierarchy of classes in which ClassC derives from ClassB, which derives from ClassA. The constructor for a subclass can call only direct superclasses. Therefore, each class constructor can call the direct superclass constructor:

In cases of multiple inheritance, the subclass constructor can call each superclass constructor. To ensure that a specific superclass constructor calling sequence is followed, call all direct superclass constructors explicitly from the most specific subclass constructor:

Related Topics