difference between "typedef enum ABCD{0,1};" and typedef enum {0,1}ABCD;

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Hi all, i want to know the difference between following two statements.

typedef enum COLOR{
RED,
WHITE
};
and
typedef enum {
RED,
WHITE
}COLOR;

Posted 7-Aug-14 23:14pm

sandeepyes

Updated 7-Aug-14 23:50pm

v2

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Comments

Andreas Gieriet 8-Aug-14 5:16am

Did you try to compile?
Andi

3 solutions

Solution 2

Both are invalid statements in C++ (as well in C).
Please see: "enumeration declaration"[^].

Posted 7-Aug-14 23:29pm

CPallini

Solution 1

Yes, both are compiling and working fine. I just want to know is any difference between them ??

Posted 7-Aug-14 23:28pm

sandeepyes

Comments

Andreas Gieriet 8-Aug-14 5:42am

They won't compile. 0 and 1 are not legal enumerators.
Andi

Stefan_Lang 8-Aug-14 5:43am

1. Use the correct [Reply] button at the top right of the comment if you want to reply to a comment. Posting a solution means you have a solution to the problem - which you have not!

2. the code that you posted doesn't compile. if you do have code that compiles, copy/paste that code. Use the green [improve question] button at the bottom right of your posting to correct it.

sandeepyes 8-Aug-14 5:47am

oh sorry, I just put those 0,1 as example. My question is what is the difference if the name ABCD comes before and after the braces.

mean to say what is the difference between
typedef enum ABCD{
RED,
WHITE
};

and
typedef enum{
RED,
WHITE
}ABCD;

Stefan_Lang 8-Aug-14 6:13am

In the first, the typedef is nonsensical since you did not specify the symbol you want to bind the typedef to - it's like writing "int;", i. e. a variable declaration without a variable.

In the second, the presence of the typedef changes the meaning of ABCD from "variable of type unnamed enum{RED,WHITE}" to "typename used as alias for the unnamed enum{RED,WHITE}"

Both versions will be usable in exactly the same way. But, either way, you should just write "enum ABCD{...}" instead, omitting the redundand typedef.

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Andreas Gieriet · Accepted Answer · 2014-08-07T23:45:00

Solution 3

Assuming you replace the 0 and 1 with legal enumerator names, then the first is a redundant typedef (you can leave it away) and the second defines an alias for an otherwise unnamed enum type.
Cheers
Andi

Posted 7-Aug-14 23:45pm

Andreas Gieriet

Comments

Stefan_Lang 8-Aug-14 5:50am

Since the question is tagged as C++, it would be fair to say that the typedef as such is nonsensical. but of course your answer is entirely correct. Have a 5

Andreas Gieriet 8-Aug-14 7:23am

Thanks for your 5!
Cheers
Andi