enum question...

[Chris Mantoulidis]

I can use enums in three ways:

typedef enum { a, b, c, d } ABCD; //this is a TYPE
enum EFGH { e, f, g, h }; //this is a TYPE too
enum { i, j, k, l } IJKL; //this however is a variable...

I believe this happens with structs too, but that's not the point.

Why are there two ways of declaring an enum type??? Isn't one way
enough? Or is the second way more C++-ish?

Thanks in advance,
cmad

 

[Ron Natalie]

Why are there two ways of declaring an enum type??? Isn't one way
enough? Or is the second way more C++-ish?

They are different. The first is an alias of the unnamed enum.

In C++ struct and enum names are themselves types names.
In C they are not, so you either have to repeat the word enum (or
struct) or use the typedef.

 

[Rolf Magnus]

I can use enums in three ways:

typedef enum { a, b, c, d } ABCD; //this is a TYPE
enum EFGH { e, f, g, h }; //this is a TYPE too
enum { i, j, k, l } IJKL; //this however is a variable...

I believe this happens with structs too, but that's not the point.

Why are there two ways of declaring an enum type???

They are different things, though the result is the same. typedef is
there to give an alias name to an existing type.
The first example defines a nameless enum type and gives it an "alias"
name of 'ABCD'. The second one creates an enum with name 'EFGH'. You
can also write:

enum EFGH { e, f, g, h};
typedef EFGH ABCD;

or even combined:

typedef enum EFGH { e, f, g, h} ABCD;

Both of those define an enum named EFGH and give them an alias name of
'ABCD'.

Isn't one way enough?

Well, one of them is just a side effect of the existance of typedef.
There is often more than one way to do the same thing.

 

[jeffc]

I can use enums in three ways:

typedef enum { a, b, c, d } ABCD; //this is a TYPE
enum EFGH { e, f, g, h }; //this is a TYPE too
enum { i, j, k, l } IJKL; //this however is a variable...

I believe this happens with structs too, but that's not the point.

Why are there two ways of declaring an enum type??? Isn't one way
enough? Or is the second way more C++-ish?

To answer your question specifically, yes the second way is more C++-ish.