(C++) Template metaprogramming

Making programs that are executed at compile time. For this it uses templates to derive types or values at compile time.

Example to calculate the factorial:

include <iostream>


template <unsigned int N>
struct factorial
{
  static unsigned const value = N * factorial<N-1>::value;
};
template <>
struct factorial<0>
{
  static unsigned const value = 1;
};
int main()
{
  std::cout
    << factorial<0>::value << std::endl
    << factorial<1>::value << std::endl
    << factorial<2>::value << std::endl
    << factorial<3>::value << std::endl
    << factorial<4>::value << std::endl
    << factorial<5>::value << std::endl
    << factorial<6>::value << std::endl
    << factorial<7>::value << std::endl
    << factorial<8>::value << std::endl
    << factorial<9>::value << std::endl
    << factorial<10>::value << std::endl
    << factorial<11>::value << std::endl
    << factorial<12>::value << std::endl;
}

External links

WikiPedia: http://en.wikipedia.org/wiki/Template_metaprogramming
The CodeProject, 'A gentle introduction to Template Metaprogramming with C++' by moliate: http://www.codeproject.com/cpp/crc_meta.asp

last edited (June 17, 2007) by bilderbikkel, Number of views: 1043, Current Rev: 2 (Diff)

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