RE: [Dev-C++] Question about pointers (beginner)

[Christian S. <sm...@xs...>]

I tried the code below with a standard DevCPP and MSVC++.

DevCPP just compiles and runs it and gives 456 for *ptr_int even before its
initialized.
MSVC++ 6 compiles it but gives an warning that the pointer hasn't been
initialized. When I try to run it, it crashes.

The code:

#include <stdio.h>

main ( )
{
  int x, *ptr_int;

  *ptr_int = 456;

  printf ("The value of ptr_int is %d\n",ptr_int);
  printf ("The value of ptr_int is %p\n",ptr_int);
  printf ("The value of *ptr_int is %d\n",*ptr_int);
  printf ("The value of &ptr_int is %p\n",&ptr_int);

  x = 123;

  ptr_int = &x;

  printf ("The value of ptr_int is %p\n",ptr_int);
  printf ("The value of *ptr_int is %d\n",*ptr_int);
  printf ("The value of x is %d\n",x);
  printf ("The value of &x is %p\n",&x);

}

> -----Original Message-----
> From: dev...@li...
> [mailto:dev...@li...]On Behalf Of Khalid
> El-Kary
> Sent: dinsdag 27 mei 2003 21:14
> To: Dev...@li...
> Subject: Re: [Dev-C++] Question about pointers (beginner)
>
>
> Did you try that code with any compiler, the line *ptr_int = 456; should
> give a segmentation fault!
> given that there's isn't a code you missed from the book :-)
>
> >From my book:
> >
> >Given x = 123 and ptr_int = &x after that *ptr_int = 456 has
> been executed.
> >What is the value of x?
> >
> >I thought it was 123 as the pointer *ptr_int is a null pointer and can't
> >have any value.
> >
> >This is how I see it:
> >
> >main ( )
> >{
> >int x, *ptr_int;
> >
> >*ptr_int = 456; /*This pointer is a null pointer at this moment right? */
> >
> >x =123;
> >ptr_int = &x; /* As x is just set to 123 and the statement
> *ptr_int = 456;
> >was executed before I would think *ptr_int would be 123 */
> >
> >}
> >
> >----------
> >
> >But the books says the value of *ptr_int at the end is 456. How come??
> >
> >Thanks for your time,
> >
> >Christian
> >
> >
> >
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