Polymorphism of function overriding and inheritance: the art of realizing flexible calls between objects

Function rewriting and inherited polymorphism are two key concepts to achieve flexible object calling in OOP: Function rewriting: the derived class redefines the function of the same name in the base class, and executes the specific implementation in the derived class when called. Polymorphism of inheritance: A derived class can be used in the same way as a base class, and when a method is called through a base class reference, its implementation in the derived class is executed.

Polymorphism of function rewriting and inheritance: the art of realizing flexible calls between objects

Preface
Polymorphism of function overriding and inheritance are two important concepts in object-oriented programming (OOP). They allow objects to perform different actions according to their types, thereby achieving code flexibility and reusability.

Function rewriting
Function rewriting refers to redefining the function of the same name in the base class in the derived class. When a derived class object calls this overridden function, the specific implementation in the derived class will be executed without calling the original implementation in the base class.

Code Example:

class BaseClass:
    def do_something(self):
        print("Base class method called")

class DerivedClass(BaseClass):
    def do_something(self):
        print("Derived class method called")

In this example, DerivedClass overrides do_something in BaseClass method. When the DerivedClass object calls the do_something method, the overridden version in DerivedClass will be executed.

Inherited polymorphism
Inherited polymorphism means that the derived class can be used in the same way as the base class. This means that you can use a reference from the base class to refer to an object of the derived class and then call a method in the base class and that method will be executed in the derived class in a way specific to it.

Code Example:

def do_something(obj):
    obj.do_something()

base_obj = BaseClass()
derived_obj = DerivedClass()

do_something(base_obj)  # 调用基类方法
do_something(derived_obj)  # 调用派生类重写方法

In this example, the do_something function is called ## using a base class reference obj #do_somethingmethod. When obj refers to the BaseClass object, the base class method will be executed; when obj refers to the DerivedClass object, the derived class override will be executed. method.

Practical CaseIn an e-commerce system, you can use polymorphism to achieve flexible payment processing. You can define a base class of
PaymentMethod and create derived classes for different payment methods (e.g. credit card, PayPal). Each derived class can override the process_payment method to process payments using a specific payment gateway.

This way you can easily switch payment methods according to the needs of your application without modifying the code that uses

PaymentMethod.

Conclusion Function overriding and inherited polymorphism are powerful tools in OOP, and they enable you to implement flexible calls between objects. By understanding these concepts, you can write code that is more flexible, reusable, and maintainable.

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