// convert string to wstring
std::wstring to_wstring(const std::string& str,
const std::locale& loc = std::locale())
{
std::vector<wchar_t> buf(str.size());
std::use_facet<std::ctype<wchar_t>>(loc).widen(str.data(),//ctype<char_type>
str.data() + str.size(),
buf.data());//把char转换为T
return std::wstring(buf.data(), buf.size());
}
// convert wstring to string with ’?’ as default character
std::string to_string(const std::wstring& str,
const std::locale& loc = std::locale())
{
std::vector<char> buf(str.size());
std::use_facet<std::ctype<wchar_t>>(loc).narrow(str.data(),
str.data() + str.size(),
' ? ', buf.data());//把T转换为char
return std::string(buf.data(), buf.size());
}
char c = 'a';
bool bl = use_facet<ctype<char>>(locale("")).is(ctype_base::lower, c);要比Convenience Functions std::islower(c,loc)效率高。
| member type | definition | description |
|---|---|---|
| char_type | The template parameter (charT) | Character type |
