代码：

#include <stdio.h>
#include <math.h>


int main ()
{
    unsigned int binary[16] = {0};
    int i, num;
    printf("Please input a number, range 0 to 65535: ");
    scanf("%d", &num);

    for (i = 15; i >= 0; i --)
    {
        if (num >= 1)
        {
            binary[i] = num % 2;
            num /= 2;
        }
    }

    for (i = 0; i < 16; i ++)
    {
        printf("%d",binary[i]);
        if ((i > 1) && ((i + 1) % 4 == 0))
            printf(" ");
        if ((i > 1) && ((i + 1) % 8 == 0))
            printf(" ");

    }
    printf("\n");
}

运行结果：