// needed for library function printf()
#include <stdio.h>

/* Normally you would put function prototypes here:

  void show_bytes(char *start, int len);
  void show_int(int x);

  Except that in this case the function declarations
  come before their first calls in the file, so they
  are not necessary.
*/

/* Takes start address of data and prints out len bytes in hex.  */
void show_bytes(char *start, int len)
{
  unsigned int i;
  // for loop doesn't need curly braces {} because single-line body
  for (i = 0; i < len; i++)
    // printf symbols:
    //  %p - print as pointer
    //  \t - tab character
    //  %x - print in hex (.2 means pad to 2 digits)
    //  \n - newline character
    printf("%p\t%#02x\n", start + i, (unsigned char)*(start + i));
  printf("\n");
}

/* Uses show_bytes() to print hex representation of integer.
   Use of sizeof() means this code will work even if int isn't 4B. */
void show_int(int x)
{
  show_bytes((char *)&x, sizeof(int));

  unsigned int bytes = 0;
  unsigned int mask = 0xff;
  while (bytes <= 3)
  {
    unsigned char value = x & mask;
    printf("x = %x, mask = %x, x&mask = %x", x, mask, value);
    //    value = value >> (bytes * 8);
    printf("\n Byte %d = 0x%.2x\n", bytes, value);
    bytes++;
    x = (unsigned int)x >> 8;
    //    mask = mask << 8;
  }
}

/* Example usage of show_int(). */
int main()
{
  int x = 0xdeadbeef; // 12345 = 0x3039
  printf("int x = %d (0x%x);\n", x, x);
  show_int(x);

  return 0;
}