访问虚函数表++ （菱形继承(public)）

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#虚函数 #多继承

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本文通过一个C++实例，详细解析了在菱形继承结构中虚函数表的布局和访问机制，展示了如何通过指针遍历虚函数表并调用各个类的虚函数。

访问菱形继承时的虚函数表

在这里插入图片描述

#include <iostream>
#include <cstdio>
#include <iomanip>
#include <string>
#include <cstdlib>
#include <cstring>
#include <queue>
#include <set>
#include <vector>
#include <map>
#include <algorithm>
#include <cmath>
#include <stack>

#define INF 0x3f3f3f3f
#define LINF 0x3f3f3f3f3f3f3f3f
#define ll long long
#define ull unsigned long long
#define uint unsigned int
#define l(x) ((x)<<1)
#define r(x) ((x)<<1|1)
#define lowbit(x) ((x)&(-(x)))
#define abs(x) ((x)>=0?(x):(-(x)))
#define ms(a,b) memset(a,b,sizeof(a))

using namespace std;

class A {
public:
	virtual void getA() {
		cout << "A" << endl;
	}
	virtual void get() {
		cout << "A get" << endl;
	}
};

class B {
public:
	virtual void get() {
		cout << "B get" << endl;
	}
	virtual void getB() {
		cout << "B" << endl;
	}
};

class C : public A, public B {
public:
	virtual void get() {
		cout << "C get" << endl;
	}
	virtual void getC() {
		cout << "C" << endl;
	}
};

class D : public A, public B {
public:
	virtual void get() {
		cout << "D get" << endl;
	}
	virtual void getD() {
		cout << "D" << endl;
	}
};

class Child : public C, public D {
public:
	virtual void get() {
		cout << "Child get" << endl;
	}
	virtual void getChild() {
		cout << "Child" << endl;
	}
};

typedef void(*FUNC)();


int main() {
	Child *child = new Child();

	int *vt = (int *)child;

	cout << "in begin" << endl;
	for (int i = 0; vt[i] != 0; i++) {
		cout << "第"<<i<<"张虚函数表" << endl;
		int *fun = (int *)(vt[i]);
		for (int i = 0; fun[i] != 0; ++i) {
			printf("function : %d :0X%x->", i, fun[i]);
			FUNC f = (FUNC)fun[i];
			f();
		}
		cout << endl;
	}

	return 0;
}