#include <stdio.h>
#include <stdlib.h>

typedef union
{
	unsigned char	raw;
	
	struct
	{
		unsigned char	high:4;
		unsigned char 	low:4;
	
	} data;
	
} bitwiseStruct;

static void prnBits(void *addr, size_t s);

void main()
{
	int		i;
	bitwiseStruct	bws;
	
	unsigned char	c;
	
	for (i = 0; i < 256; i++)
	{
		bws.raw = (unsigned char) i;
		
		printf("For value %3d:  bits [", (int) bws.raw);
		
		prnBits(&bws.raw, sizeof(char));
		
		c = bws.data.high;
		printf("]; high [");	
		prnBits(&c, sizeof(char));
		
		c = bws.data.low;		
		printf("]; low [");
		prnBits(&c, sizeof(char));
		
		printf("]\n");
	}
}

static void prnBits(void *addr, size_t s)
{
	int	i, j;
	
	unsigned char	*a = (unsigned char *) addr;
	
	for (i = 0; i < s; i++)
	{
		for (j = 7; j >= 0; j--)
		{
			printf("%c", *a & 1 << j ? '1' : '0');
		}

		a++;
	}
}

For value 240:  bits [11110000]; high [00001111]; low [00000000]

For value 240:  bits [11110000]; high [00000000]; low [00001111]