2. Symbolic constant: (you can define structural constants) constants defined by #define and const!
The difference between these two constants is:
Constants defined by #define do not occupy memory except literal constants of strings, so they can't take the address of constants, just macro replacement, for example:
① # Define the name "Pang Dong";
A literal constant whose essence is a string will occupy the "static storage area";
② # Define MAX 256
Essentially, it is a literal constant of shaping and will not allocate memory.