Answer 1

#include <stdio.h>

int main() {
int a,*ptr=NULL,**p=NULL;
scanf("%d",&a);
ptr=&a;
p=&ptr;
printf("%d\n",a);
printf("%d\n",*ptr);
printf("%d\n",**p);
printf("%p\n",&a);
printf("%p\n",ptr);
printf("%p\n",&ptr);
return 0;
}

Answer 2

A pointer that stores the address of a pointer to an integer would have the type int**. You are simply missing an asterisk when declaring 'p'.