求助：自学中题看不懂，看了书上的答案还是没看懂题，怎么办啊？？
求解释这道题到底想做什么？书中的编程练习题：
书中答案：
程序代码：
#include <limits.h>
void set_bit(char bit_array[], unsigned bit_number);
void clear_bit(char bit_array[], unsigned bit_number);
void assign_bit(char bit_array[], unsigned bit_number, int value);
int test_bit(char bit_array[], unsigned bit_number);
unsigned character_offset(unsigned bit_number);
unsigned bit_offset(unsigned bit_number);
void
set_bit(char bit_array[], unsigned bit_number)
{
bit_array[character_offset(bit_number)] |=
1 << bit_offset(bit_number);
}
void
clear_bit(char bit_array[], unsigned bit_number)
{
bit_array[character_offset(bit_number)] &=
~(1 << bit_offset(bit_number));
}
void
assign_bit(char bit_array[], unsigned bit_number, int value)
{
if (value != 0)
set_bit(bit_array, bit_number);
else
clear_bit(bit_array, bit_number);
}
int
test_bit(char bit_array[], unsigned bit_number)
{
return (
bit_array[character_offset(bit_number)]
& 1 << bit_offset(bit_number)
) != 0;
}
unsigned
character_offset(unsigned bit_number)
{
return bit_number / CHAR_BIT;
}
unsigned
bit_offset(unsigned bit_number)
{
return bit_number % CHAR_BIT;
}
