/* Unpack a byte from an int. */

#include <limits.h>

char unpack(int p, int k)                  /* k = 0, 1, 2, or 3 */
{
   int        n = k * CHAR_BIT;            /* n = 0, 8, 16, or 24 */
   unsigned   mask = 255;                  /* low-order byte */

   mask <<= n;
   return ((p & mask) >> n);
}