Thread: Pointer

It might help if you posted something that will compile.

Code:

int i;
int *p = &i;  // points to the int
int **p = &p; // points to the pointer, which in turn points to the int
printf("%p %p %p\n", (void*)&i, (void*)p, (void*)(*pp) );

Originally Posted by Shree Ge

Certainly, my code complies in VS 2016 without problem.

Originally Posted by Shree Ge

Salem you have changed the entire code. I never asked for double pointer declaration and initialization (int **p = &p).
int *p;
p = &p;
printf ("%d %d %d", p, &p, *p);
Finely works in Visual Studio 2013 and GCC

You say it works fine, but are you getting any warnings? You're not providing a complete compilable example for us to reference.

For what it's worth, your example is wrong. "p" is a pointer to int, but you're treating it as if it were a pointer to a pointer.

Are you asking if a pointer can point to itself? I can't find anything in the rules that doesn't allow this (though I haven't looked very hard, nor can I find a good reason to do so).

What's even worse is when you try to dereference an uninitialized *p, which is undefined behavior.

Oh really....

Code:

$ cat main.c
#include <stdio.h>
 
int main()
{
  int *p;
  p = &p;
  printf ("%d %d %d", p, &p, *p);
  return 0;
}
$ gcc -Wall main.c
main.c: In function ‘main’:
main.c:6:5: warning: assignment from incompatible pointer type [-Wincompatible-pointer-types]
   p = &p;
     ^
main.c:7:11: warning: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘int *’ [-Wformat=]
   printf ("%d %d %d", p, &p, *p);
           ^
main.c:7:11: warning: format ‘%d’ expects argument of type ‘int’, but argument 3 has type ‘int **’ [-Wformat=]

I've no idea what your question is, if you keep posting junk like p = &p

There is no such thing in C where T and T* are the same thing.