Thank you for your explanation for my last question
I want to know a little more:)
>According to the C++ standard, you're not allow to pass by value.
What is a C++ standard? Do I have that :-)
>basic_ios(const basic_ios& ); // not defined
>basic_ios& operator=(const basic_ios&); // not defined
>istream and istringstream both derive from basic_ios.
>The standard defines basic_ios copy constructor
>and assignment operator as both private and not defined.
You mean 'private' shoul avoid basic_ios to be copied by me in compiling time?
And how do I know what belong to basic_ios ?