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Francis DS
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 Posted: Mon Mar 01, 2004 12:28 pm Post subject: Using a #define'd integer to create a #define'd string |
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Problem:
I have about 2,500 .h files with macro definitions like this:
#define MAXITEMS 400
where the value of MAXITEMS can vary in each file
(the 400 is an example).
I need to define MAXITEMS_STR to be a string with
the same sequence of digits as the integer.
IOW, I something like:
#define MAXITEMS_STR "400"
or even better do away with the macro and move to C++.
Something like:
const char * MAXITEMS_STR = "400";
I am trying to accomplish this in one .h file. Something like this:
mynew.h file
----------------
#include "the file that contains the definition of MAXITEMS as an integer"
// define MAXITEMS_STR using the value of MAXITEMS
#define MAXITEMS_STR "value of MAXITEMS" <--- how can I achieve this?
const char* MAXITEMS_STR = "value of MAXITEMS" <--- or this?
-fds
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Francis Glassborow
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| Posted: Mon Mar 01, 2004 5:19 pm Post subject: Re: Using a #define'd integer to create a #define'd string |
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In message <8653cb1a.0402291802.37919154 (AT) posting (DOT) google.com>, Francis DS
<francisds (AT) hotmail (DOT) com> writes
| Quote: | Problem:
I have about 2,500 .h files with macro definitions like this:
#define MAXITEMS 400
where the value of MAXITEMS can vary in each file
(the 400 is an example).
I need to define MAXITEMS_STR to be a string with
the same sequence of digits as the integer.
IOW, I something like:
#define MAXITEMS_STR "400"
or even better do away with the macro and move to C++.
Something like:
const char * MAXITEMS_STR = "400";
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I think that is a job for a program:-) I guess that using something such
as Perl or Python might be appropriate. Trying to fix it with some C or
C++ mechanism seems a poor idea to me.
--
Francis Glassborow ACCU
Author of 'You Can Do It!' see http://www.spellen.org/youcandoit
For project ideas and contributions: http://www.spellen.org/youcandoit/projects
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Sebastian Kapfer
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| Posted: Mon Mar 01, 2004 5:40 pm Post subject: Re: Using a #define'd integer to create a #define'd string |
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On Mon, 01 Mar 2004 07:28:38 -0500, Francis DS wrote:
| Quote: | Problem:
I have about 2,500 .h files with macro definitions like this:
#define MAXITEMS 400
where the value of MAXITEMS can vary in each file (the 400 is an
example).
I need to define MAXITEMS_STR to be a string with the same sequence of
digits as the integer. IOW, I something like:
#define MAXITEMS_STR "400"
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#include <iostream>
#define NUMBER 400
#define STRINGIZE2(x) #x
#define STRINGIZE(x) STRINGIZE2(x)
const char *NUMBER_STR STRINGIZE(NUMBER)
int main()
{
int i = NUMBER;
const char *i_str = NUMBER_STR;
std::cout << i << " " << i_str << "n";
return 0;
}
Probably, you can also do this with some tricky templates and abandon the
C++ preprocessor. The above is the classic C-style solution.
--
Best Regards, | This signature is currently under construction.
Sebastian | Please check back later!
| Quote: | --------------------------------------------------------
mailbox in "From" silently drops any mail > 20k
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Maciej Sobczak
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| Posted: Mon Mar 01, 2004 5:45 pm Post subject: Re: Using a #define'd integer to create a #define'd string |
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Hi,
Francis DS wrote:
| Quote: | Problem:
I have about 2,500 .h files with macro definitions like this:
#define MAXITEMS 400
where the value of MAXITEMS can vary in each file
(the 400 is an example).
I need to define MAXITEMS_STR to be a string with
the same sequence of digits as the integer.
IOW, I something like:
#define MAXITEMS_STR "400"
or even better do away with the macro and move to C++.
Something like:
const char * MAXITEMS_STR = "400";
|
You can experiment with this:
#include <iostream>
#define MAXITEMS 400
// more such definitions
// ...
// these two macros will automatically define the stringized
// version of the given macro
#define STRINGIZE_HELPER(m) #m
#define STRINGIZE(m) const char * m##_STR = STRINGIZE_HELPER(m);
// now, let's define MAXITEMS_STR
STRINGIZE(MAXITEMS)
// more such automatic definitions
// ...
int main()
{
// print the stringized value
std::cout << MAXITEMS_STR << 'n';
}
The solution above requires from you that you write those STRINGIZE(...)
definitions yourself.
The other possible solution is to write a script that will go through
your headers and that will smartly recognize #defs with integer values
(or maybe you already have some pattern that can make this recognition
easier) and generate the "const char *" definitions automatically.
If the number of your definitions is larger than a couple of tens, then
I'd certainly go the scripting way.
If you plan to have such code in the future, you can also experiment
with this:
#define DEF_NUM_AND_STR(name, val)
const long name = val;
const char *name##_str = #val;
and later:
DEF_NUM_AND_STR(MAXITEMS, 400)
// ...
This way, you get two definitions (one for long and one for string) in a
single line. If you later change the name or value, there is a single
place to do so.
--
Maciej Sobczak : http://www.msobczak.com/
Programming : http://www.msobczak.com/prog/
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Ben Hutchings
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| Posted: Tue Mar 02, 2004 11:33 am Post subject: Re: Using a #define'd integer to create a #define'd string |
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Francis DS wrote:
| Quote: | Problem:
I have about 2,500 .h files with macro definitions like this:
#define MAXITEMS 400
where the value of MAXITEMS can vary in each file
(the 400 is an example).
|
I don't think I want to know why you're doing this.
| Quote: | I need to define MAXITEMS_STR to be a string with
the same sequence of digits as the integer.
IOW, I something like:
#define MAXITEMS_STR "400"
or even better do away with the macro and move to C++.
snip |
If you need the conversion to be done at compile time you must use the
preprocessor:
#define STR2(x) #x
#define STR(x) STR2(x)
#define MAXITEMS_STR STR(MAXITEMS)
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