istream              Formatted Input Stream


            The istream stream is used for non-file formatted input.
    The cin class is derived from istream. The important member
    functions of istream include:

 istream &get(ch);    Get one char from stream associated with object
 char &ch;              Location to put character at

 istream &read(buf, num);     Read num bytes from this object's stream
 unsigned char *buf;    Data buffer
 int num;               Number of bytes to read

 int eof();      Return nonzero value when the end of the file is reached.

 istream &seekg(offset, origin);      Move data get pointer
 streamoff offset;      Type defined in IOSTREAM.H
 seek_dir origin;       Seek_dir is an enumeration; possible values:
                           ios::beg  =  Beginning
                           ios::cur  =  Current location
                           ios::end  =  End