pointer error...

[a R T u n]

what do you think is wrong with this?

#include <iostream>

int foobar (int *pi1)
{
*pi1 = 1024;
return *pi1;
}

int main ()
{
int *pi2 = 0;

int ival = foobar (pi2);

return 0;
}

[Alf P. Steinbach]

* a R T u n:

[homework]

See <url: http://www.parashift.com/c++-faq-lite/how-to-post.html#faq-5.2>.

--
A: Because it messes up the order in which people normally read text.
Q: Why is it such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet and in e-mail?

[Karl Heinz Buchegger]

a R T u n wrote:

what do you think is wrong with this?

#include <iostream>

int foobar (int *pi1)
{
*pi1 = 1024;
return *pi1;
}

int main ()
{
int *pi2 = 0;

int ival = foobar (pi2);

return 0;
}

dereferencing a null pointer has undefined behaviour.

--
Karl Heinz Buchegger
kb******@gascad.at

[upashu2]

>>Is it homework or quiz?

int *pi2 = 0; Okey Your address is null. *pi1 = 1024; I am giving you 1024 doller at your address.(But Postmaster is not
accepting the letter with null address.)return *pi1;
int ival = foobar (pi2);

You haven't get it. Why?
You forget to given your address.
First construct your house either on stack or on heap, then give the
address of that.
int pi = 0; /// Now &pi is valid address of your house pi constructed
on stack.
int ival = foobar (&pi);

[a R T u n]

just none... only a newbie in pointers...

[Jim Langston]

----- Original Message -----
From: "a R T u n" <mu********@gmail.com>
Newsgroups: comp.lang.c++
Sent: Tuesday, July 26, 2005 1:26 AM
Subject: Re: pointer error...

just none... only a newbie in pointers...

Did you understand the answers?

int *p = 0; // Defines a pointer pointing to "nothing" (a NULL pointer)

You can't use this before you point it to some place to actually store the
interger.

*p = 1024; // Error, p isn't pointing to anything your program owns.

p = new int; // allocates sizeof(int) memory, p now "points" to it.

*p = 1024; // Now 1024 goes into those sizeof(int) bytes that were
allocated.