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C++ implicit copy constructor for a class that contains other objects（5个答案）
Conditions for automatic generation of default/copy/move ctor and copy/move assignment operator?（3个答案）
3天前关闭。
当我在c++中使用std容器时，我发现一个有趣的部分我不明白，有人能帮忙吗？第二个类包含第一个类的容器，当第二个类创建一个局部对象并将其推入容器时，它会在函数之外死亡，但它仍然有一个在容器中工作，只有一个构造函数工作，但有两个析构函数工作，为什么？？？？
第一类是：

#include <iostream>

using namespace std;

class Test1{
    private:

    public:

        Test1(){

            cout << "this is in." << endl;
        };

        ~Test1(){

            cout << "this is out." << endl;
        };

        void thiswork(){

            cout << "he is still working" <<  endl;
        }

};

第二类是：

#include "test1.hh"
#include <vector>

using namespace std;

class Test2{

    public:

        Test2(){

            cout << "this is test2 creat." << endl;
        };

        ~Test2(){

            cout << "this is test2 die" << endl;
        };

        void init(){

            Test1 first;
            test2.push_back(first);
            cout << "into vector" << endl;
            test2[0].thiswork();
        };

        void dummy(){

            cout << "into dummy" << endl;
            test2[0].thiswork();
        };
    private:

        vector<Test1> test2 = {};
};

测试代码：

#include "test2.hh"

int main(){

    Test2 test = Test2();

    test.init();

    test.dummy();

    return 0;
}

令人惊讶结果：

this is test2 creat.
this is in.
into vector
he is still working
this is out.
into dummy
he is still working
this is test2 die
this is out.