#include <iostream>
#include <typeinfo.h>
using namespace std;class Base//基类是多态类
{
public:virtual void f(){cout<<"Inside Base."<<endl;}
};
class Derived : public Base
{
public:void f(){cout<<"Inside Derived."<<endl;}
};void main()
{  cout<<"Start"<<endl; Base *bp,b_ob;Derived *dp,d_ob;//-------------------------------------dp=dynamic_cast<Derived*>(&d_ob);//派生类对象的指针“强制转换为”派生类对象的指针 OKif(dp){cout<<"Cast from Derived* to Derived* Ok."<<endl;dp->f();}elsecout<<"Error!"<<endl;//--------------------------------------bp=dynamic_cast<Base*>(&d_ob);//派生类对象的指针“强制转换为”基类对象的指针 OKif(bp){cout<<"Cast from Derived* to Base* OK."<<endl;bp->f();}elsecout<<"Error!"<<endl;//---------------------------------bp=dynamic_cast<Base*>(&b_ob);//基类对象的指针“强制转换为”基类对象的指针 OKif(bp){cout<<"Cast from Base* to Base* OK."<<endl;bp->f();}elsecout<<"Error!"<<endl;//-------------------------------------bp=dynamic_cast<Derived*>(&b_ob);//基类对象的指针“强制转换为”派生类对象的指针 Errorif(bp){cout<<"Cast from Base* to Base* OK."<<endl;bp->f();}elsecout<<"Cast from Base* to Base* not OK."<<endl;//=====================================================bp=&d_ob;dp=dynamic_cast<Derived*>(bp);//指向派生类的基类指针“强制转换为”派生类对象的指针 OKif(dp){cout<<"casting bp to a Drived* OK."<<endl;cout<<"because bp is really pointing to a Derived object."<<endl;dp->f();}else cout<<"Error!"<<endl;//-------------------------------------------------------bp=&b_ob;//bp指向基类型的对象dp=dynamic_cast<Derived*>(bp);//指向基类型对象的指针“强制转换为”派生类对象的指针 OKif(dp)cout<<"Error!"<<endl;else{cout<<"Now casting bp to a Drived* is not ok."<<endl;cout<<"because bp is really pointing to a Base object."<<endl;}//---------------------------------------------------------dp=&d_ob;//dp指向基类型的对象bp=dynamic_cast<Base*>(dp);//指向派生类型对象的指针“强制转换为”指向基类对象的指针 OKif(dp){cout<<"Casting dp to a base* is ok"<<endl;bp->f();}elsecout<<"Error"<<endl;cout<<"End"<<endl;
}

Base *bp;
Derived *dp;
// compare type at run time of two objects
if (typeid(*bp) == typeid(*dp))
{// bp and dp point to objects of the same type
}
// test whether run time type is a specific type
if (typeid(*bp) == typeid(Derived))
{// bp actually points a Derived
}