c++ - 如何调用破坏函数？

Question

#include<iostream>
using namespace std;
class Monster {

  public: 
  Monster() {cout << "with out argument. \n";}
  Monster(int sz) { cout << "Monster created.\n"; }
  ~Monster() { cout << "Monster destroyed.\n"; }

  int GetSize() { return itsSize; }
  void SetSize(int str) { itsSize = str; }

private:
  int itsSize;
};

int main()
{
  Monster *m;
  m =new Monster[3];
  for(int i = 0; i < 3; i++)
     m[i] = i; // constructor with argument is getting called for each elements after which why destructor is getting called for each element.          
  delete []m;
  return 0;
}

Output:
with out argument. 
with out argument. 
with out argument. 
Monster created. // Monster constructor with argument is getting called.
Monster destroyed. // 1. Why this destructor is getting called after each call of constructor.
Monster created.
Monster destroyed. //2.
Monster created.
Monster destroyed. //3.
Monster destroyed.
Monster destroyed.
Monster destroyed.

当我用值初始化 Monster 对象数组时，参数化的构造函数被调用，紧接着为什么调用析构函数？

Answer 1

m =new Monster[3];

这里创建了三个对象，为每个对象调用了默认构造函数。这就是为什么您会看到消息没有参数。

m[i] = i;

首先，使用 Monster(int) 构造函数在右侧创建临时 Monster。这就是您看到消息 Monster created. 的原因。接下来，调用赋值运算符。接下来，您的临时 Monster 被删除。这就是您看到 Monster destroyed. 的原因。

delete []m;

阵列中的三个怪物被摧毁。

---

为了更好地理解这种情况，我建议您将this 的地址添加到您的所有消息中。