----- Original Message -----
From: "agarwal_bajrang" <agarwal_bajrang@yahoo.com>
To: <C-Guru@yahoogroups.com>
Sent: Saturday, May 01, 2004 5:15 PM
Subject: [C-Guru] help needed in c
> Anyone please tell me the difference between NULL and 0 in C.
>
Note the following points:
* NULL is defined as either
#define NULL 0
or
#define NULL (void*)0
in the header <stddef.h>
* Technically, there is no difference between NULL and 0.
* Integers and pointers may not be of same size. On some machines,
pointers can even be wider than integers!
* The only integer value that can portably be assigned to a pointer is
0; assinging any other integer is implementation-defined.
> When we write const keyword then where this value will stored in
> memory?
>
Note the following points:
* An implementation may choose to place a `const' qualified object into
the program's read-only area.
* No write through the const qualified lvalues.
* If the address of an unqualified object, or qualified ONLY by `const',
is never taken, then the implementation may NOT allocate storage for it.