For normal declaration of variable, a statement is like this int MAX 1000, which can be clared at the very beginning (before all functions), and become a global variable. If it’s declared within a function, it’s called local variable.
For constants, for both global constant and local constant, the statement is like this one, const int MAX 1000. In addition, there’s another way to set and replace a symbol with a predefined value. To declare such a constant (symbol), a statement like this #define MAX 1000 is used instead. #define statement can also be used to declare macro.