sick template-stuff aka compile-time programs [Archive]

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0rp

February 23rd, 2005, 09:13

Code:

#include <stdio.h>



template<int N> class Factorial

{

public:

	enum { value = N * Factorial<N-1>::value };

};



class Factorial<1>

{

public:

    enum { value = 1 };

};



int main(int argc, char **args)

{

	printf("%d\n", Factorial<10>::value);

	return 0;

}

solving algorithms at compiletime
funny shit

dELTA

February 23rd, 2005, 09:38

Hehe, I once wrote a complete executable linker in pure compile-time MASM macro language. It even used self modifying macro code, and produced very nice and compact viral code too...

Pffft, two-line factorial solvers...

bilbo

February 23rd, 2005, 12:22

Quote:

[Originally Posted by 0rp]solving algorithms at compiletime

Great example of templates!
In fact the resulting disassembly is simply

Code:



        push 375F00h

        push "%d"

        call _printf

I was asking why in the hell enum had been used... In fact, in the net, you can find also the variant which replaces

Code:



        enum { value = N * Factorial<N-1>::value };

        enum { value = 1 };

with

Code:



        static const int value = N * Factorial<N-1>::value;

        static const int value = 1;

Then I understood. It is a bug in Micro$oft (oops... the temp forum $...) compiler! See http://support.microsoft.com/kb/241569/EN-US/

Regards, bilbo