[C++]对象的销毁机制

销毁时会按照从后向前的顺序销毁，也就是说，越在后面定义的对象会越早销毁。其中的原因就是函数是在栈中保存的，因此，先定义的对象先压栈，所以在退栈时就会后销毁。而如果参数有多个的话，大多数编译器是从右开始压栈的，也就是参数列表最右边的变量最先压栈，所以参数列表最右边的变量会在最后销毁。

代码如下：

 #include<iostream>

 using namespace std;

 class Matter {
 public:
     Matter(int id) : _identifier(id)
         {cout << "Matter from " << _identifier << endl; }
     ~Matter()
         { cout << "Matter Bye from " << _identifier << endl; }

 private:
     const int _identifier;
 };

 class World {
 public:
     World(int id) : _identifier(id),_matter(id)
         {cout << "Hello from " << _identifier << endl; }
     ~World() { cout << "Bye from " << _identifier << endl; }

 private:
     const int _identifier;
     Matter _matter;
 };

 World TheWorld();

 int main() {
     World smallWorld();
     cout << "hello from main()\n";
     World oneMoreWorld();

     return ;
 }

输出结果

Matter from
Hello from
Matter from
Hello from
Hello from main()
Matter from
Hello from
Bye from
Matter Bye from
Bye from
Matter Bye from
Bye from
Matter Bye from