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  1. #include <boost/mpl/int.hpp>
  2. #include <boost/mpl/at.hpp>
  3. #include <boost/mpl/map.hpp>
  4.  
  5. namespace mpl = boost::mpl;
  6.  
  7. template<class T>
  8. struct size_traits{
  9.     typedef typename boost::mpl::at<
  10.         mpl::map<
  11.             mpl::pair<mpl::int_<sizeof(bool)>,      bool>,
  12.             mpl::pair<mpl::int_<sizeof(char)>,      char>,
  13.             mpl::pair<mpl::int_<sizeof(short)>,     short>,
  14.             mpl::pair<mpl::int_<sizeof(int)>,       int>,
  15.             mpl::pair<mpl::int_<sizeof(long)>,      long>,
  16.             mpl::pair<mpl::int_<sizeof(long long)>, long long>,
  17.             mpl::pair<mpl::int_<sizeof(float)>,     float>,
  18.             mpl::pair<mpl::int_<sizeof(double)>,    double>
  19.         >,
  20.         mpl::int_<sizeof(T)>
  21.     >::type type;
  22. };
  23.  
  24. #include <iostream>
  25. #include <typeinfo>
  26.  
  27. int main(){
  28.     std::cout
  29.         << typeid(size_traits<bool>::type     ).name() << "\n"
  30.         << typeid(size_traits<char>::type     ).name() << "\n"
  31.         << typeid(size_traits<short>::type    ).name() << "\n"
  32.         << typeid(size_traits<int>::type      ).name() << "\n"
  33.         << typeid(size_traits<long>::type     ).name() << "\n"
  34.         << typeid(size_traits<long long>::type).name() << "\n"
  35.         << typeid(size_traits<float>::type    ).name() << "\n"
  36.         << typeid(size_traits<double>::type   ).name() << "\n"
  37.         << typeid(size_traits<void*>::type    ).name() << "\n";
  38. 	return 0;
  39. }
Success #stdin #stdout 0.02s 2724KB
comments (?)
stdin 
Standard input is empty
stdout 
c
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https://ideone.com/pkiS4
language:
C++ (gcc 8.3)
created:
12 years ago
visibility:
public

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