What is the difference between an enum and a series of preprocessor #defines?
At the present time, there is little difference. Although many people might have wished otherwise, the ANSI standard says that enumerations may be freely intermixed with integral types, without errors. (If such intermixing were disallowed without explicit casts, judicious use of enums could catch certain programming errors.) The primary advantages of enums are that the numeric values are automatically assigned, and that a debugger may be able to display the symbolic values when enum variables are examined. (A compiler may also generate nonfatal warnings when enums and ints are indiscriminately mixed, since doing so can still be considered bad style even though it is not strictly illegal). A disadvantage is that the programmer has little control over the size (or over those nonfatal warnings). References: K&R II Sec. 2.3 p. 39, Sec. A4.2 p. 196; H&S Sec. 5.5 p. 100; ANSI Secs. 3.1.2.5, 3.5.2, 3.5.2.2 . 9.2: I heard that structures could be assigned to variables and passed to and from fu
