typeidRTTI.cpp；dynamic_cast<Derive22&>(b2);

// typeidRTTI.cpp : Defines the entry point for the console application.//#include "stdafx.h"#include <iostream>using namespace std;int main( void ){// sample 1    cout << typeid(1.1f).name() << endl;// sample 2    class Base1    {    };    class Derive1 : public Base1    {    };    Derive1 d1;    Base1& b1 = d1;    cout << typeid(b1).name() << endl; // 输出"class Base1",因为Derive1和Base1之间没有多态性// sample 3, 编译时需要加参数 /GR    class Base2    {        virtual void fun( void ) {}    };    class Derive2 : public Base2    {    };    Derive2 d2;    Base2& b2 = d2;    cout << typeid(b2).name() << endl; // 输出"class Derive2",因为Derive1和Base1之间有了多态性// sample 4    class Derive22 : public Base2    {    };    // 指针强制转化失败后可以比较指针是否为零，而引用却没办法，所以引用制转化失败后抛出异常    Derive2* pb1 = dynamic_cast<Derive2*>(&b2);    cout << boolalpha << (0!=pb1) << endl; // 输出"true",因为b2本身就确实是Derive2    Derive22* pb2 = dynamic_cast<Derive22*>(&b2);    cout << boolalpha << (0!=pb2) << endl; // 输出"false",因为b2本身不是Derive2    try {        Derive2& rb1 = dynamic_cast<Derive2&>(b2);        cout << "true" << endl;    } catch( bad_cast )    {        cout << "false" << endl;    }    try {        Derive22& rb2 = dynamic_cast<Derive22&>(b2);        cout << "true" << endl;    } catch( ... ) // 应该是 bad_cast,但不知道为什么在VC++6.0中却不行    {        cout << "false" << endl;    }    return 0;}