Change value of variable through pointer : Pointer Calculation « Pointer « C Tutorial

1. C Tutorial
2. Pointer
3. Pointer Calculation

#include <stdio.h>

int main(void)
{
  long num1 = 0;
  long num2 = 0;
  long *pnum = NULL;

  pnum = &num1;                              
  *pnum = 2;                                 
  ++num2;                                    
  num2 += *pnum;                             

  pnum = &num2;                              
  ++*pnum;                                   

  printf ("\nnum1 = %ld  num2 = %ld  *pnum = %ld  *pnum + num2 = %ld\n",
                                      num1, num2, *pnum, *pnum + num2);
  return 0;
}

num1 = 2  num2 = 4  *pnum = 4  *pnum + num2 = 8