pointereg1.c

//pointer eg.

#include <stdio.h>
void main()
{
   int num = 10;
   int *ptr1 = &num;
   int *ptr2;
   int *ptr3 = 0;
   if (ptr1 == 0)
   {
      printf("ptr1:NULL\n");
   }
   else
   {
      printf("ptr1:NOT NULL\n");
   }
   if (ptr2 == 0)
   {
      printf("ptr2:NULL\n");
   }
   else
   {
      printf("ptr2:NOT NULL\n");
   }
   if (ptr3 == 0)
   {
      printf("ptr3:NULL\n");
   }
   else
   {
      printf("ptr3:NOT NULL\n");
   }
}