39 return is.good() && state;
45 return state && os.good();
virtual bool read(std::istream &is)
read the data from a stream
virtual bool write(std::ostream &os) const
write the data to a stream
virtual bool write(std::ostream &os) const
write the data to a stream
virtual bool read(std::istream &is)
read the data from a stream
some general case utility functions
constexpr double cst(long double v)