How does inheritance achieve polymorphism in C++?

In C++, polymorphism is achieved through inheritance, allowing objects to have different behaviors even if they have the same common base class. Inheritance is a method of creating new classes where the new class (derived class) inherits members from an existing class (base class) and can add new members. When a virtual function is called using a pointer or reference of a derived class type, the overridden method in the derived class is called.

How to implement polymorphism through inheritance in C++

What is polymorphism?

Polymorphism allows objects to have different behaviors even if they have the same common base class. In C++, polymorphism is achieved using inheritance.

Inheritance

Inheritance is a method of creating new methods of a class, where the new class (derived class) inherits from an existing class (base class). A derived class inherits all members (data and functions) of the base class and can also add new members of its own.

How is polymorphism achieved through inheritance?

In polymorphism, a derived class object can have a pointer or reference to its base class type. When a virtual function is called using a pointer or reference of a derived class type, the overridden method in the derived class is called.

Example:

class Animal {
public:
    virtual void makeSound() {
        cout << "Animal makes a sound" << endl;
    }
};

class Dog : public Animal {
public:
    void makeSound() override {
        cout << "Woof woof!" << endl;
    }
};

class Cat : public Animal {
public:
    void makeSound() override {
        cout << "Meow meow!" << endl;
    }
};

int main() {
    Animal* animal = new Cat(); // 指向 Cat 对象的 Animal 指针
    animal->makeSound(); // 输出 "Meow meow!"
}

In the above example:

• Animal is the base class.
• Dog and Cat are derived classes.
• makeSound is a virtual function, overridden in derived classes.
• animal is a base class pointer pointing to a derived class object.

When animal->makeSound() is called, makeSound overridden in the derived class (Cat) will be called Method, output "Meow meow!".

The above is the detailed content of How does inheritance achieve polymorphism in C++?. For more information, please follow other related articles on the PHP Chinese website!