Managing input streams: class istream

Class istream objects are specialized for input; as for ostream, they are derived from ios, so you can use any of the general-purpose methods from that base class. Declarations for this class also come from `iostream.h'.

Constructor: istream::istream ()

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

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

You can also call the 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. You can use the second optional argument tie to specify a related output stream as the initial value for ios::tie.

If you give the istream a streambuf explicitly, using this constructor, the sb is not destroyed (or deleted or closed) when the ostream is destroyed.