Re: why cin.getline does not wait for an input?

From: Tim Roberts (timr_at_probo.com)
Date: 12/19/04 

Date: Sat, 18 Dec 2004 22:21:23 -0800

"Geoff" <Geoff@discussions.microsoft.com> wrote:
>
>Thank you very much very good, this was well worth the wait.
>
>Just out of curiosity, does the stream into cin share the memory on each
>time it's called, is it a union or something similar?

I'm not sure what you're asking. The buffer for cin is just a stream of
bytes. When you do this:

   int i;
   cin >> i;

The C++ compiler knows this is a "right shift" operator between an object
of type istream (or istreambuf or something like that) and an object of
type int. It searches for a function that takes those two parameters and
finds:

    istream& operator>> (istream&, int);

It then includes a call to that function in your code. It is that function
that knows how to read characters from the stream and convert them to an
integer. Same thing happens with a different type. If you do this:

   int i;
   char str[40];
   cin >> i >> str;

You get two calls. One to
   istream& operator>>(istream&,int);
and one to
   istream& operator>>(istream&,char*); 

-- 
- Tim Roberts, timr@probo.com
  Providenza & Boekelheide, Inc

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