#include <stdio.h>
#include <limits.h>
#define ONE_BYTE 8
#define TWO_BYTE 16

typedef unsigned char BIT_TYPE;
#define BIT_NBIT (CHAR_BIT * sizeof(BIT_TYPE))
#define BIT_SIZE(N) (((N) + BIT_NBIT-1) / BIT_NBIT)

int main()
{
 BIT_TYPE bit_array[BIT_SIZE(ONE_BYTE)]={0};
 BIT_TYPE bit_array2[BIT_SIZE(TWO_BYTE)]={0};

 printf("bit_array ist %d Bytes gross\n",sizeof(bit_array));
 printf("bit_array2 ist %d Bytes gross\n",sizeof(bit_array2));
 return 0;
}