Arithmetics

/* add to pointer */
#include <stdio.h>
 
int main()
{
  int a;
  int *p;
 
  a = 10;
  p = &a;
 
  printf("value of a is: %d\n", a);
  printf("the address of a is stored in p: %p\n", p);
  printf("size of a is: %d\n", sizeof(a));
 
  p++;
 
  printf("the address of p+1 moved %d bytes up: %p\n", sizeof(a), p);
  printf("the value of memory pointed by p+1 is garbage: %d\n", *p);
 
  return 0;
}

/* Host byte order: Little Endian / Least significant bit first */
#include <stdio.h>
 
int main()
{
  printf("size of int : %d\n", sizeof(int));
  printf("size of char: %d\n", sizeof(char));
 
  /* 1025 : 00000000 00000000 00001000 00000001 */
  int a = 2049;
  int *p0 = &a;
 
  printf("p0 points to address: %p\n", p0);
  printf("p0 points to value: %d\n", *p0);
 
  char *p1;
  p1 = (char *)p0;
  printf("p1 points to address: %p\n", p1);
  printf("p1 points to value: %d\n", *p1);
 
  p1++;
  printf("p1++ points to address: %p\n", p1);
  printf("p1++ points to value: %d\n", *p1);
 
 
  p0++;
  printf("p0++ points to address: %p\n", p0);
  printf("p0++ points to value: %d\n", *p0);
 
  return 0;
}

/* void pointer */
#include <stdio.h>
 
int main()
{
  int a = 10;
  int *p = &a;
 
  printf("address is: %p\n", p);
  printf("value is: %d\n", *p);
 
  void *p0;
  p0 = p;
  printf("address is: %p\n", p0);
  /* invalid use of void expression */
  // printf("value is: %d\n", *p0);
 
  return 0;
}