Revealing the principle of function rewriting: how subclasses control the behavior of parent classes

Question: What is the principle of function rewriting? Answer: Function overriding allows subclasses to control parent class behavior by redefining methods inherited from the parent class by declaring a method with the same name and using the override keyword. Steps: Declare the virtual method in the constructor of the subclass and mark it with the virtual keyword. Specify the method's return value type, name, and parameter list, which are the same as the parent class method. Use the override keyword to explicitly declare the method as an override.

Revelation of the principle of function rewriting: How subclasses control the behavior of parent classes

Overriding is a key concept in object-oriented programming A crucial concept that allows subclasses to redefine methods inherited from parent classes. Through overriding, a subclass can customize the behavior of its parent class while maintaining compatibility with the base class code.

Understanding overriding

Overriding is declared in the constructor of the subclass, in the following format:

virtual <return type> <function name>(<parameter list>) override;

• virtual keyword indicates that this method can be overridden by subclasses.
• <return type> Specifies the return value type of the method.
• <function name> is the name of the overridden method.
• <parameter list> is the parameter list of the method.
• override keyword explicitly declares that the method is an override of the parent class method.

Practical case

To illustrate function rewriting, we create a Shape# with the draw() method ## Base class and a subclass named Circle:

class Shape {
public:
    virtual void draw() { cout << "Drawing Shape" << endl; }
};

class Circle : public Shape {
public:
    void draw() override { cout << "Drawing Circle" << endl; }
};

Shape The draw() method is declared as virtual, which means it can be overridden by the Circle class. In the Circle class, the draw() method is redefined to print "Drawing Circle".

How overriding works

When a subclass object calls the

draw() method, the compiler dynamically selects the appropriate accomplish. If the object is a Circle instance, the overridden Circle::draw() method will be called. Otherwise, it calls the base class's Shape::draw() method.

Advantages

Function overriding provides the following advantages:

Allows subclasses to customize the behavior of their parent class as needed.
• Maintain code scalability and reusability.
• Promote code refactoring without modifying the base class.

Notes

The following precautions should be followed when rewriting:

Method signature (return type and parameter list) Must be the same as the parent class method.
• The overridden method cannot have a more restrictive access level than its parent class method.
• Overridden methods typically use the
• override keyword to provide compile-time checking and prevent accidental overrides.

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