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──The Microsoft iostream Classes────────────────────────────────────────────
 
  Description
 
  The istream class provides the basic capability for sequential and
  random-access input. An istream object has a streambuf-derived object
  attached, and the two classes work together; the istream class does the
  formatting, and the streambuf class does the low-level buffered input.
 
  You can use istream objects for sequential disk input if you first
  construct an appropriate filebuf object. More often, you will use the
  predefined stream object cin (which is actually an object of class
  istream_withassign), or you will use objects of classes ifstream (disk
  file streams) and istrstream (string streams).
 
  Derivation
 
  It is not always necessary to derive from istream in order to add
  functionality to a stream; consider deriving from streambuf instead, as
  illustrated in Chapter 19 of the <Class Libraries User's Guide>. The
  ifstream and istrstream classes are examples of istream-derived classes
  that construct member objects of predetermined derived streambuf
  classes.
 
  You can add manipulators without deriving a new class.
 
  If you add new extraction operators for a derived istream class, then
  the rules of C++ dictate that you must reimplement all the base class
  extraction operators. See the "Derivation" section of class ◄ostream►
  for an efficient reimplementation technique.
 
  #include <iostream.h>
 
  See Also
 
  ◄streambuf►, ◄ifstream►, ◄istrstream►, ◄istream_withassign►
 
  Public Members
 
  Construction/Destruction
 
  ◄istream►   Constructs an istream object attached to an existing object
              of a streambuf-derived class.
 
  ◄~istream►   Destroys an istream object.
 
  Prefix/Suffix Functions
 
  ◄ipfx►   Check for error conditions prior to extraction operations
           (input prefix function).
 
  ◄isfx►   Called after extraction operations (input suffix function).
 
  Input Functions
 
  ◄get►        Extracts characters from the stream up to, but not
               including, delimiters.
 
  ◄getline►    Extracts characters from the stream (extracts and discards
               delimiters).
 
  ◄read►       Extracts data from the stream.
 
  ◄ignore►     Extracts and discards characters.
 
  ◄peek►       Returns a character without extracting it from the stream.
 
  ◄gcount►     Counts the characters extracted in the last unformatted
               operation.
 
  ◄eatwhite►   Extracts leading white space.
 
  Other Functions
 
  ◄putback►   Puts characters back to the stream.
 
  ◄sync►      Synchronizes the stream buffer with the external source of
              characters.
 
  ◄seekg►     Changes the stream's get pointer.
 
  ◄tellg►     Gets the value of the stream's get pointer.
 
  Operators
 
  ◄operator >>►   Extraction operator for various types.
 
  Protected Members
 
  ◄istream►   Constructs an istream object.
 
  Manipulators
 
  ◄ws►   Extracts leading white space.
 
 
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