Enum

BitWise Operations

Your enumeration needs to be powers of two :

enum {

   TAKES_DAMAGE = 1,
   GRABBABLE = 2,
   LIQUID = 4,
   SOME_OTHER = 8

};

Or in a more readable fashion :

enum {

   TAKES_DAMAGE = 1 << 0,
   GRABBABLE = 1 << 1,
   LIQUID = 1 << 2,
   SOME_OTHER = 1 << 3

};

Why ? Because you want to be able to combine flags with no overlapping, and also be able to do this:

if(myVar & GRABBABLE) {

   // grabbable code

}

... Which works if the enumeration values look like this :

TAKES_DAMAGE: 00000001
GRABBABLE:    00000010
LIQUID:       00000100
SOME_OTHER:   00001000

So, say you've set myVar to GRABBABLE | TAKES_DAMAGE, here's how it works when you need to check for the GRABBABLE flag:

myVar:     00000011
GRABBABLE: 00000010 [AND]
-------------------
           00000010 // non-zero => converts to true

If you'd set myVar to LIQUID | SOME_OTHER, the operation would have resulted in :

myVar:     00001100
GRABBABLE: 00000010 [AND]
-------------------
           00000000 // zero => converts to false

Match any

enum {

   TAKES_DAMAGE = 1 << 0,
   GRABBABLE = 1 << 1,
   LIQUID = 1 << 2,
   SOME_OTHER = 1 << 3,
   ANY = 0b1111

};