C++ 虚拟函数与虚继承：揭示多重继承中的复杂性
虚拟函数
虚拟函数是 C++ 中一种特殊类型的成员函数，允许派生类重写基类中的函数。当基类指针或引用指向派生类对象时，将会调用派生类的虚拟函数。
class Shape {
public:
virtual double area() const = 0; // 纯虚函数
};
class Rectangle : public Shape {
public:
Rectangle(double width, double height) : m_width(width), m_height(height) {}
double area() const override { return m_width * m_height; } // 重写虚函数
private:
double m_width;
double m_height;
};
虚继承
虚继承是一种技术，用于解决多重继承中发生的菱形继承问题（也称为多重继承的歧义性）。
class Animal {
public:
virtual void speak() const { cout << "Animal speaks" << endl; }
};
class Dog : virtual public Animal { // 虚继承
public:
void speak() const override { cout << "Dog barks" << endl; }
};
class Cat : virtual public Animal { // 虚继承
public:
void speak() const override { cout << "Cat meows" << endl; }
};
class SiberianHusky : public Dog, public Cat { // 多重继承
public:
void speak() const override { cout << "Siberian Husky howls" << endl; }
};
虚继承确保每个基类（Animal）在派生类（SiberianHusky）中只存在一个实例，从而避免菱形继承问题。
实战案例
#include <iostream>
using namespace std;
class Shape {
public:
virtual double area() const = 0;
};
class Rectangle : public Shape {
public:
Rectangle(double width, double height) : m_width(width), m_height(height) {}
double area() const override { return m_width * m_height; }
private:
double m_width;
double m_height;
};
class Circle : public Shape {
public:
Circle(double radius) : m_radius(radius) {}
double area() const override { return M_PI * m_radius * m_radius; }
private:
double m_radius;
};
int mAIn() {
// 创建形状的父类指针
Shape* shape;
// 创建矩形对象并将其分配给父类指针
shape = new Rectangle(5, 10);
cout << "矩形面积：" << shape->area() << endl;
// 创建圆形对象并将其分配给父类指针
shape = new Circle(3);
cout << "圆形面积：" << shape->area() << endl;
return 0;
}
以上就是C++ 虚拟函数与虚继承：揭示多重继承中的复杂性的详细内容。
