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An enumeration constant is a member of an enumeration. Enumeration constant can be used to represent an integer constant expression that has a value representable as an int. Unlike const-qualified objects, enumeration constants do not require that storage is allocated for the value so it is not possible to take the address of an enumeration constant.
A preprocessing directive of the form:
# define identifier replacement-list
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defines an _object-like_ macro that causes each subsequent instance of the macro name to be replaced by the replacement list of preprocessing tokens that constitute the remainder of the directive \[[ISO/IEC 9899-1999|AA. C References#ISO/IEC 9899-1999]\]. |
#define:
- operates at compile time
- consumes no memory (though this is not too important)
- can use in compile-time constant expression
- uses different syntax; can make mistake with ;
- can't create pointers to
- no type checking
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