How does Enum allocate Memory on C?

Question

I'm trying to work with C and Assembly (intelx8086) language.

I'm also using one class that was implemented by a friend of mine. It has a

typedef enum data_10 {a=0,b=7,c=10,} data_10_type;

I want to work with this class bitwise (AKA construct it/destroy it on Assembly). My question is, how much memory does "enum" take?

Answer 1

Although it may vary from compiler to compiler, enum typically takes the same size as an int. To be sure, though, you can always use sizeof( data_10_type );

Answer 2

Why don't you print it?

/* C99 */
#include <stdio.h>

typedef enum { a = 0, b = 7, c = 10 } data_10_type;
printf("%zu\n", sizeof(data_10_type));

The identifiers in an enumerator list are declared as constants that have type int (C11 §6.7.2.2 Enumeration specifiers), so sizeof(data_10_type) is often equal to sizeof(int), but it isn't necessary!

BTW, if you want to have a size in bits, just use the CHAR_BIT constant (defined in <limits.h>), which indicates how many bits there are in a single byte).

/* C99 */
#include <limits.h>
#include <stdio.h>

typedef enum { a = 0, b = 7, c = 10 } data_10_type;
printf("%zu\n", sizeof(data_10_type) * CHAR_BIT);