Enumerate type

I got compile error (Borland C/C++ 5.1) with
enumerate types. Does anyone know what wrong?

Here is my C program.

Code:

#include <stdio.h>
typedef enum {NONE, OFF, ON} Light;
typedef enum {PRESS, DEPRESS, NONE} Button;
typedef enum {RUN, STOP, OFF} State;

int main()
{
  Light  L;
  Button B;
  State  S;
  /* do computation here...*/
  return 0;
}

Also I have been struggling to find the sizeof
(enum) enumerate type. It always display 4 bytes
when I use sizeof(enum) regardless of the number
of identifiers (elements) of enumerate type I created.
I really appreciate your help.

I am not an expert... but shouldn't

typedef enum {NONE, OFF, ON) Light;

be

typedef enum {NONE, OFF, ON} Light;

??



COOL PROGRAMS @ www.akilla.tk

Thanx for pointed out that little typo.
you are not expert but I guess you are a guru.
Please explain why the code above has error???

Originally posted by dv007
Thanx for pointed out that little typo.
you are not expert but I guess you are a guru.
Please explain why the code above has error???

K&R page 215
The identifiers in enumeration type are declared as constants of type int .... .

so variables of enum type are like integers
therefore sizeof(Light) should give to the same value as sizeof (int)
Are you confusing enums with arrays , in case of arrays the sizeof returns total number of bytes taken by the entire array ?

But you know what causing compile error for
enumerate types I delared in my for program???

>But you know what causing compile error for enumerate types I delared in my for program???

Code:

typedef enum {NONE, OFF, ON} Light;
typedef enum {PRESS, DEPRESS, NONE} Button;
typedef enum {RUN, STOP, OFF} State;

Notice that NONE and OFF are used twice each. This is an error as you can only use an enum identifier once in the program. It is usually a good idea to either prefix or postfix your identifiers with the type as well to avoid this little redefinition problem:

Code:

typedef enum { LIGHT_NONE,   LIGHT_OFF,      LIGHT_ON }    Light;
typedef enum { BUTTON_PRESS, BUTTON_DEPRESS, BUTTON_NONE } Button;
typedef enum { STATE_RUN,    STATE_STOP,     STATE_OFF }   State;

-Prelude

Thanx a lot, Prelude.
But you know why those defined enum types interfere each other?

set A = {1, 2 ,3}; <=> enum type A
set B = {3, 4, 5}; <=> enum type B
set C = {2, 6, 18}; <=> enum type C
They are completely different set.
I think Ada or Pascal raise no compile error
for those IDENTIFIERs in completely different
enumerate type? Right? Correct me if I'm wrong?
Can you explain a litle bit more about this
interference among different enumerate types in C.
Since Light has none business with State.

Again, Thanx Prelude.

>But you know why those defined enum types interfere each other?
Because the standard specifies such behavior.

From the C99 Standard, section 6.7.2.2

Code:

Semantics
3 The identifiers in an enumerator list are declared as constants that have type int and
may appear wherever such are permitted.107)
<snip>
107) Thus, the identifiers of enumeration constants declared in the same scope shall all be distinct from
each other and from other identifiers declared in ordinary declarators.

-Prelude

Get rid of the typedef in this particular situation. It is detrimental to your program because it only serves to hide the type which is not a good thing when debugging or having someone else read your program. Just a suggestion.