int main()
{

int *d=0;
printf("%d\n",*d);

return 0;
}

this works fine.

>cc legal.c
> ./a.out
0

if i change the statement int *d=0; to int *d=1; i see the error.

cc: "legal.c", line 6: error 1522: Cannot initialize a pointer with an integer constant other than zero.

so its obvious that it will allow only zero.i want to know what happens inside the memory when we do this int *d=0 which is making it valid syntax.

I am just asking this out of curiosity!