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Enumeration Constants
Enumeration constant constants 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 allocated consume memory. No storage is allocated for the value so it is not possible to take the address of an enumeration constant.
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enum { max = 15 };
int a[max]; /* OK outside function */
const int *p;
p = &max; /* error: '&' on enum constant */
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Enumeration constants do not allow the type of the value to be specified. An enumeration constant whose value can be represented as an int is always an int.
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Macro names do not observe the scope rules that apply to other names. Consequently, macros might substitute in unexpected unanticipated places with unanticipated unexpected results.
Object-like macros do not consume memory, and consequently, it is not possible to create a pointer to one. Macros do not provide for type checking, as they are textually replaced by the preprocessor.
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