#include<iostream>
#include<list>
using namespace std;

class A{
    int i;
    static int num;
public:
    A():i(0){ cout<<"A()" <<endl; num ++;}
    A(int ii):i(ii){ cout<<"A(int)" <<endl; num ++;}
    ~A(){ cout<< "~A" <<endl;}
    A(const A& a){
        i = a.i;
        cout<<"A(const A&)"<<endl;
        num ++;
    }
    A& operator =(const A& a){
        cout<<"operator="<<endl;
        i = a.i;
        return *this;

    }
    void print(){
        cout<<i<<endl;
    }
    void printN(){
        cout<< " num = "<<num<<endl;
    }
};

int A::num = 0;

int main(){
    //A a(1);
    //A b = a;
    //A c;
    //c = a;
    //c.print();
    //a.printN();
    list<A> li;
    li.push_back(A(2));
    list<A>::iterator it = li.begin();
    (*it).printN();
}

输出结果：
A(int)//A2临时对象

A(const A&)//li.push_back(A(2))调用其复制构造函数
~A//离开临时对象作用域A调用其析构函数
 num = 2
~A //程序结束
从输出结果可以看出传到list中的是对象的拷贝。