#include <stdio.h>

// Declare some global integers:
int i = 5;
int j = 6;
int sum;

int main ()
{
  // Int pointer declarations:
  int *intPtr;
  int *intPtr2;
  int *intPtr3;

  // First, let's print the address of variable i:
  printf ("Variable i is located at address %p\n", &i);

  // Now extract the address of variable i into the pointer:
  intPtr = & i;

  // Print.
  printf ("The int at memory location %p is %d\n", intPtr, *intPtr);

  // Let's do some arithmetic.
  intPtr2 = & j;
  sum = (*intPtr) + (*intPtr2);
  printf ("The sum of %d and %d is %d\n", *intPtr, *intPtr2, sum);

  // Now for something stranger:
  printf ("The integer at location %p is %d\n", (intPtr+1), *(intPtr+1)); 
  printf ("The integer j=%d is at location %p\n", j, &j);

  // Let's see what the default initial value of intPtr3 is:
  if (intPtr3 == NULL) {
    printf ("intPtr3 has been initialized to NULL\n");
  }
  else {
    printf ("intPtr3 has been initialized to %p\n", intPtr3);
  }
}