One, the definition of pointer
Definition of pointer: P is a pointer to a.
*P is the content of the unit pointed to by P, which is a.
Second, the size of the space occupied by pointer type data
Check the memory space occupied by pointer type data.
It occupies 4 bytes under the 32-bit operating system, and 8 bytes under the 64-bit operating system.
Three, null pointer and wild pointer
Four, pointer-const modified pointer
4.1 Constant pointer
4.2 Pointer constants
4.3const modifies both pointers and constants
Five, pointers and functions
