Why use enum when #define is just as efficient? [duplicate]

Question

So an enum works like this:

enum {
  false,
  true
}

which is equivalent to

int false = 0
int true = 1

Why wouldn't I substitute enum with #define?

#define FALSE 0
#define TRUE 1

To me, it seems like they are interchangeable. I'm aware that #define is able to handle arguments, hence operates in an entirely different way than enum. What exactly are the main uses of enum when we have #define in this case?

If I were to guess, as the #define is a preprocessor feature, enum would have some runtime advantages. How far off am I?

Thanks in advance.

Answer 1

The advantages of enum show up when you have a long list of things you want to map into numbers, and you want to be able to insert something in the middle of that list. For example, you have:

pears 0
apples 1
oranges 2
grapes 3
peaches 4
apricots 5

Now you want to put tangerines after oranges. With #defines, you'd have to redefine the numbers of grapes, peaches, and apricots. Using enum, it would happen automatically. Yes, this is a contrived example, but hopefully it gives you the idea.

Answer 2

I find it useful for debugging in an environment such as gdb since enum values are handled at compile time (where #define is a preprocessor macro) and thus available for introspection.