The GNU C++ Iostream Library - Iostream

Input and output together: class iostream

If you need to use the same stream for input and output, you can use an object of the class iostream , which is derived from both istream and ostream .

The constructors for iostream behave just like the constructors for istream .

Constructor iostream::iostream ()

When used without arguments, the iostream constructor simply allocates a new ios object, and initializes the input counter (the value reported by istream::gcount ) to 0 .

Constructor iostream::iostream (streambuf* sb [, ostream* tie])

You can also call a constructor with one or two arguments. The first argument sb is a streambuf* ; if you supply this pointer, the constructor uses that streambuf for input and output.

You can use the optional second argument tie (an ostream* ) to specify a related output stream as the initial value for ios::tie .

As for ostream and istream , iostream simply uses the ios destructor. However, an iostream is not deleted by its destructor.

You can use all the istream , ostream , and ios methods with an iostream object.