C++之使用继承的虚函数表

#include 
using namespace std;

class Father {
public:
	virtual void func1() { cout << "Father::func1" << endl; }
	virtual void func2() { cout << "Father::func2" << endl; }
	virtual void func3() { cout << "Father::func3" << endl; }
	void func4() { cout << "非虚函数：Father::func4" << endl; }
public:  //为了便于测试，特别该用public
	int x = 100;
	int y = 200;
};

class Son : public Father {
public:
	void func1() { cout << "Son::func1" << endl; }
	virtual void func5() { cout << "Son::func5" << endl; }
};

typedef void (*func_t)(void);

int main(void) {
	Father father;
	Son  son;

	// 含有虚函数的对象的内存中，最先存储的就是“虚函数表”
	cout << "son对象地址：" << (int*)&son << endl;

	int* vptr = (int*)*(int*)&son;
	cout << "虚函数表指针vptr：" << vptr << endl;

	for (int i = 0; i < 4; i++) {
		cout << "调用第" << i + 1 << "个虚函数：";
		((func_t) * (vptr + i))();
	}
	
	for (int i = 0; i < 2; i++) {
		// +4 是因为先存储了虚表指针
		cout << *(int*)((int)&son + 4 + i * 4) << endl;
	}

	system("pause");
	return 0;
}

执行效果：