C++ ClassesLesson 39Free preview

C++ Polymorphism

This lesson is part of C++ · All levels

Summary

Polymorphism allows one interface to be used for many forms: methods with the same name can behave differently on a derivative class. The key is virtual function, which makes the call via a pointer or reference base selecting the version belonging to the actual object. If a class has a pure virtual, it becomes abstract and cannot be directly created as an object.

Key points

Virtual function can be override in class derived and selected dynamically (runtime).
The explicit override is written with an override to prevent typing the signature incorrectly.
Pure virtual is written as virtual void f() = 0; and makes a class abstract.
Without a virtual, the pointer-base call is always running the base version.

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