prototype模式

#include <iostream>
using namespace std;

class base
{
public:
    int x;
    base():x(3){}
    virtual base* clone()=0;
    virtual ~base(){}
    void f(){
        cout<<x<<endl;
    }
};


class derieved : public base
{
public:

    derieved(){}
    virtual base* clone(){
        return new derieved(*this);
    }
};

int main()
{
    base* kaka=new derieved();
    base* kaka_copy=kaka->clone();
    kaka_copy->f();
    return 0;
}