本文共 1761 字，大约阅读时间需要 5 分钟。

#include 
   
    #include 
    
     using namespace std;class Base {
     public:    int a;    virtual void g() {
           cout << "Base::g" << endl;    }    virtual void h() {
           cout << "Base::h" << endl;    }    virtual void f() {
           cout << "Base::f" << endl;    }};class Derive : public Base {
     public:    int a;    void print() {
           cout << "print" << endl;    }    virtual void f1() {
           cout << "Derive::f1" << endl;    }    virtual void f() {
           cout << "Derive::f" << endl;    }    virtual void f(char a) {
           cout << "Derive::f char a" << endl;    }    virtual void g() {
           cout << "Derive::g" << endl;    }    virtual void h() {
           cout << "Derive::h" << endl;    }};int main(int argc, char *argv[]) {
       // typedef void(*pFun) (void);    using pFun = void (*)(void);    {
           Base b;        cout << "虚函数表地址：" << (long *)(&b) << endl;        cout << "虚函数表 — 第一个函数地址：" << (long *)*(long *)(&b)  << endl;        // Invoke the first virtual function，3种写法等价。。        pFun p1 = reinterpret_cast
     
      (*(long *)(((long *)(&b))[0]));        auto p2 = (pFun) ((long *) * (long *)(&b))[1];        pFun p3 = (pFun) * ((long *) * (long *)(&b) + 2);        p1();        p2();        p3();    }    {
           Derive d;        // 打印方法1        long **table = (long **)&d;        for (int i = 0; i < 7; ++i) {
               auto pf = (pFun)table[0][i];            pf();        }        /* 打印方法2        for (int i = 0; i < 7; ++i) {            auto pf = (pFun)(long)((long *) * (long *)(&d))[i];            pf();        }        */    }    {
           // 虽然在Derive虚函数表中有 f1()，但是无法通过父类指针访问没有覆盖的函数        //Base1 *b1 = new Derive();        //b1->f1();  //编译出错    }    return 0;}
     
    
   

转载地址：http://xecii.baihongyu.com/