c++中vector中的拷贝构造过程

#include <iostream>
#include <vector>
class Data{
public:
    Data(int i):v(i){
        std::cout<<"ctor"<<std::endl;
    }
    Data(const Data &d){
        v=d.v;
        std::cout<<"copy"<<d.v<<std::endl;
    }
    Data(Data &&d) {
        v=d.v;
        std::cout << "move"<<d.v<< std::endl;
        }
    operator =(const Data &d){
        std::cout<<"copy assign "<<d.v<<std::endl;
    }
    ~Data(){
         //std::cout<<"dtor"<<std::endl;
    }
    int get(){return v;}
private:
    int v=-1;
};
int test_fun(){
    std::vector<Data> vec;
    //vec.reserve(4);
    std::cout<<"cap:"<<vec.capacity()<<std::endl;
    vec.push_back(Data(1));
    std::cout<<"cap:"<<vec.capacity()<<std::endl;
    vec.push_back(Data(2));
    std::cout<<"cap:"<<vec.capacity()<<std::endl;
    vec.push_back(Data(3));
    std::cout<<"cap:"<<vec.capacity()<<std::endl;
    std::cout<<vec.size()<<std::endl;
    for(auto ele:vec){
        std::cout<<ele.get()<<std::endl;
    }
}
int main(){
    //Data d1,d2;
    test_fun();
    return 0;
}

 本文代码主要测试vector在插入元素时，一共调用了多少次元素的拷贝构造函数。在vector空间发生扩容时，vector会调用元素的拷贝构造函数。
Reference:
[1]c++中vector的拷贝构造过程