指针是一个特殊的变量，它里面存储的数值被解释成为内存里的一个地址。 要搞清一个指针需要搞清指针的四方面的内容：指针的类型，指针所指向的 类型，指针的值或者叫指针所指向的内存区，还有指针本身所占据的内存区。-Pointer is a special variable, the value stored inside it is interpreted as a memory address. To find out a pointer to a pointer need to find out four aspects: a pointer type, pointer type, the pointer value or called pointer points to memory area, as well as the pointer itself occupies memory area.