Difficulty in understanding the MACRO.

[Vish]

Please let me know how this macro works and please provide an example
for, how to call it in my main() function.

#include <stdio.h>
#define MY_ENUM_BEGIN(etype) typedef enum etype##e {
#define MY_ENUM_END(etype) } etype##t
Thanks in advance
Vishal.

[bjrnove]

Vish wrote:

Please let me know how this macro works and please provide an example
for, how to call it in my main() function.

#include <stdio.h>
#define MY_ENUM_BEGIN(etype) typedef enum etype##e {
#define MY_ENUM_END(etype) } etype##t

A macro basically gets translated into code before compilation. The
above macro will work something like this:

MY_ENUM_BEGIN(my_enum_type)
zero,
one,
two,
five = 5
MY_ENUM_END(my_enum_type);

This will be translated into:

typedef enum my_enum_typee {
zero,
one,
two,
five = 5
} my_enum_typet;

--
bjrnove

[Jean-Claude Arbaut]

Le 15/06/2005 15:23, dans
11**********************@g43g2000cwa.googlegroups. com, «*bjrnove*»
<bj*****@gmail.com> a écrit*:

Vish wrote:

Please let me know how this macro works and please provide an example
for, how to call it in my main() function.

#include <stdio.h>
#define MY_ENUM_BEGIN(etype) typedef enum etype##e {
#define MY_ENUM_END(etype) } etype##t

A macro basically gets translated into code before compilation. The
above macro will work something like this:

MY_ENUM_BEGIN(my_enum_type)
zero,
one,
two,
five = 5
MY_ENUM_END(my_enum_type);

This will be translated into:

typedef enum my_enum_typee {
zero,
one,
two,
five = 5
} my_enum_typet;

Wow ! I prefer the second one. Just for clarity's sake :-)

[john_bode]

Vish wrote:

Please let me know how this macro works and please provide an example
for, how to call it in my main() function.

#include <stdio.h>
#define MY_ENUM_BEGIN(etype) typedef enum etype##e {
#define MY_ENUM_END(etype) } etype##t

During the preprocessing phase, all occurrences of MY_ENUM_BEGIN(x) are
replaced with the text typedef enum xe { (the ## operator in the
preprocessor merges tokens), and all occurrences of MY_ENUM_END(x) are
replaced with the text } xt. So in your main() function, you'd write

MY_ENUM_BEGIN(colors)
blue,
red,
green,
cyan,
magenta,
yellow,
white,
black
MY_ENUM_END(colors);

which, after preprocessing, would be replaced with

typedef enum colorse {
blue,
red,
green,
cyan,
magenta,
yellow,
white,
black
} colorst;

This is an example of preprocessor abuse, adds zero clarity or
readability to the code, and is bad style IMO.