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From: sdm@cs.brown.edu (Scott Meyers)
Newsgroups: comp.lang.c++
Subject: istream::putback(char c)
Message-ID: <71302@brunix.UUCP>
Date: 8 Apr 91 19:00:07 GMT
Sender: news@brunix.UUCP
Reply-To: sdm@cs.brown.edu (Scott Meyers)
Organization: Brown University Department of Computer Science
Lines: 24

From the istream man page:

          insp=&ins.putback(c)
               Attempts to back up ins.rdbuf().  c  must  be  the
               character   before   ins.rdbuf()'s   get  pointer.
               (Unless other activity  is  modifying  ins.rdbuf()
               this is the last character extracted from ins.) If
               it is not, the effect is undefined.   

Two questions:

    1.  Why am I limited to putting back the last character I removed?  
        There is no such limitation for ungetc in the standard C library.

    2.  Given that I am limited to putting back the last character I 
        read, why does putback take a parameter?

All illumination appreciated,

Scott


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