[code:1]
#include <stdio.h>
#include <limits.h>
#include <conio.h>
int pack( char, char, char, char );
void unpack( int, char *, char *, char *, char * );
void bit_print( int );
void main (void) {
int num=3, i;
int packed_num = pack('a','b','c','d');
printf("abcd= ");
bit_print( packed_num );
unpack( packed_num, &(packed_num >> CHAR_BIT), &(packed_num >> CHAR_BIT*2),
&(packed_num >> CHAR_BIT*3), &(packed_num >> CHAR_BIT)*4 );