c++ - generic typetrait to convert to string or double -

i need type trait convert input string or double. have this:

template<typename t> struct sh_trait{ }; template<> struct sh_trait<float>{ typedef double type; }; template<> struct sh_trait<double>{ typedef double type; }; template<> struct sh_trait<char*>{ typedef std::string type; }; template<> struct sh_trait<const char*>{ typedef std::string type; }; template<std::size_t n> struct sh_trait<const char[n]> { typedef std::string type; }; template<std::size_t n> struct sh_trait<char[n]> { typedef std::string type; }; template<> struct sh_trait<std::string>{ typedef std::string type; }; template<> struct sh_trait<tstring>{ typedef std::string type; }; 

and using as

void f(t input) {   sh_trait<t>::type myvalue(input);   class template_class(myvalue);   ... } 

i doing because template_class specialized double , string.

the point is: suppose user use example int. want convert double, have add line. possibile write more generic cover cases?

no c++11, no boost, c++03

you can implement base template has std::string typedef. , can specialize other integral types using sfinae:

template <typename t, typename = void> struct sh_trait {     typedef std::string type; };  template <typename t> struct sh_trait<t, typename std::enable_if<std::is_integral<t>::value>::type> {     typedef double type; };  static_assert( std::is_same<sh_trait<int>::type, double>::value ); // doesn't run 

here it's test program.