智能指针与STL容器

#include "boost/shared_ptr.hpp"#include <vector>#include <iostream>class A{public: virtual void sing() { std::cout <<"A::sing " <<number<<std::endl; } A() { number=counter+1; counter++; }protected: virtual ~A() { std::cout<<"~A "<<number<<std::endl; }; static int counter; int number;};int A::counter=0;class B : public A{public: virtual void sing() { std::cout << "B:sing "<<number<<std::endl; } virtual ~B() { std::cout<<"~B "<<number<<std::endl; }};boost::shared_ptr<A> createA(){ boost::shared_ptr<A> p(new B()); return p;}int main(){ typedef std::vector<boost::shared_ptr<A> > container_type; typedef container_type::iterator iterator; container_type container; for (int i=0;i<10;++i) { container.push_back(createA()); } std::cout << "The choir is gathered: /n"; iterator end=container.end(); for (iterator it=container.begin();it!=end;++it) { (*it)->sing(); } system("pause");}