为什么“解构主义”调用多于“构造者”调用？

Question

我正在尝试使用C++学习stl，我注意到deconstruct调用比construct调用多，我想知道我是否遗漏了什么。

以下是代码：

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

class Person {
  friend ostream &operator<<(ostream& os, const Person &p) {
    os << p.name << endl;
    return os;
  }
  string name;

public:
  Person() {
    cout << "created " << this->name << endl;
  };
  Person(string name):
    name{name} {
      cout << "created " << this->name << endl;
    }
  ~Person() {
    cout << "deconstructor " << this->name << endl;
  }
  bool operator<(const Person &rhs) const {
    return this->name < rhs.name;
  }

  bool operator==(const Person &rhs) const {
    return (this->name == rhs.name);
  }
};

int main(int argc, char** argv) {
    vector<Person> vec {{"test1"}, {"test2"}};
    Person p {"test2"};
    vector<Person>::iterator it = find(vec.begin(), vec.end(), p);
    Person p2 {"test3"};
    vec.insert(it, p2);
    for (auto &p : vec) {
      cout << p;
    }
}

这是输出：

created test1
created test2
deconstructor test2
deconstructor test1
created test2
created test3
deconstructor test2
deconstructor test1
test1
test3
test2
deconstructor test3
deconstructor test2
deconstructor test2
deconstructor test3
deconstructor test1

test1已经被解构了三次，但只创建了一次。

有什么解释吗？

谢谢。

Answer 1

不要忘记创建副本构造函数。

Person(const Person &p): name{p.name} {
    cout << "created " << this->name << endl;
}