Arithmetic conversions

From: garfaus_at_[hidden]
Date: 2001-09-28 01:55:16

Just another idea for implementing usual arithmetic
conversions between types. Perhaps it might be useful.

It is is used as

  arithmetic_conversion<A, B>::result

where 'result' is the resulting type from the usual
arithmetic conversions between type A and type B.

Regards
--
Gabriel Netterdag
#include <cstddef>
template<std::size_t N> struct selected;
template<> struct selected<1> { typedef int           type; };
template<> struct selected<2> { typedef unsigned int  type; };
template<> struct selected<3> { typedef long          type; };
template<> struct selected<4> { typedef unsigned long type; };
template<> struct selected<5> { typedef float         type; };
template<> struct selected<6> { typedef double        type; };
template<> struct selected<7> { typedef long double   type; };
template<std::size_t N>
struct sized { typedef char (&type)[N]; };
sized<1>::type selector(int);
sized<2>::type selector(unsigned int);
sized<3>::type selector(long);
sized<4>::type selector(unsigned long);
sized<5>::type selector(float);
sized<6>::type selector(double);
sized<7>::type selector(long double);
template<typename A, typename B>
struct arithmetic_conversion {
  typedef typename selected<sizeof(selector(true ? A() : B()))>::type 
result;
};