常量指针与指针常量

非常好的回答：简洁，清晰，深刻，简短
https://stackoverflow.com/questions/1143262/what-is-the-difference-between-const-int-const-int-const-and-int-const

以下是引用：
Read it backwards (as driven by Clockwise/Spiral Rule):

• int* - pointer to int
• int const * - pointer to const int
• int * const - const pointer to int
• int const * const - const pointer to const int