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Subject: Re: why learn C?
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From: Markus E Leypold
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Date: Thu, 12 Apr 2007 20:05:35 +0200
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Hyman Rosen <hyrosen@mail.com> writes:

> kevin cline wrote:
>> Preprocessor macros are quite out of fashion for C++ programming.
>
> Unfortunately so. They're good for quite a bit of things,
> especially when you want to code a little "database" table
> of properties to be "queried" for the implementation.
>
> #define QuotesTableData(IMPL) \
> 	IMPL(stock, "Security Name", string) \
> 	IMPL(date, "Quote Date", time_t) \
> 	IMPL(bid, "Bid Price", double) \
> 	IMPL(ask, "Ask Price", double)
>
> struct QuotesTable {
> 	#define QuotesEnumImpl(name, title, type) name,
> 	enum { QuotesTableData(QuotesEnumImpl), N };
> 	#define QuotesMembersImpl(name, title, type) type m_##name;
> 	QuotesTableData(QuotesMembersImpl)
> 	#define QuotesPropertiesImpl(name, title, type) \
> 		type get_##name() const { return m_##name; } \
> 		void set_##name(const type &v) { m_##name = v; } \
> 		string title_##name() const { return title; }
> 	QuotesTableData(QuotesPropertiesImpl)
> };


Without trying to understand ypur example in depth: This is -- of
course -- only necessary because C/C++ has no way to specify a
constant array (i.e. a "array literal").

Regards -- Markus