An area of the stack associated with a particular function call. 一个关联特殊函数调用的堆栈区域。
The destructor is a special member function that can be used to do whatever resource deallocation is needed.It serves as the complement to the constructors of the class. 析构函数就是这样的一个特殊函数，它可以完成所需的资源回收，作为类构造函数的补充。
