See https://en.cppreference.com/w/cpp/io/basic_ios/operator_bool and https://en.cppreference.com/w/cpp/io/basic_ios/operator!.
I think that operator! is redundant because of the user-defined operator bool.
See https://en.cppreference.com/w/cpp/io/basic_ios/operator_bool and https://en.cppreference.com/w/cpp/io/basic_ios/operator!.
I think that operator! is redundant because of the user-defined operator bool.