How to override base class function in C++?

In C, function overriding allows a derived class to override a base class function to extend or modify its behavior. The syntax is: Have the same function name Have the same function signature Use the override keyword

Comprehensive guide to function rewriting in C

In C, function overriding allows derived classes to override functions in base classes. This is useful when extending base class functionality or modifying its behavior.

Syntax

To override a base class function, the function in the derived class must:

• Have the same name as the base class function
• Have the same signature (parameter list and return value)
• Use the override keyword

For example, consider the following base class:

class Base {
public:
    virtual void print() { std::cout << "Base class" << std::endl; }
};

To override the print() function, derived classes can use the following syntax:

class Derived : public Base {
public:
    override void print() { std::cout << "Derived class" << std::endl; }
};

Practical case

Consider a Shape base class and a Circle derived class:

class Shape {
public:
    virtual double area() { return 0; }
};

class Circle : public Shape {
public:
    double radius;

    override double area() {
        return 3.14 * radius * radius;
    }
};

In the main() function, we can use virtual method scheduling to call these two methods :

int main() {
    // 创建一个圆形对象
    Circle circle;
    circle.radius = 5;

    // 通过基类指针调用派生类函数
    Shape* shape = &circle;
    double area = shape->area();

    std::cout << "Area of the circle: " << area << std::endl;

    return 0;
}

Output:

Area of the circle: 78.5

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