showBits();

void showBits(unsigned num)
{
    unsigned i;
    unsigned mask = 1 << 7; // 1000 0000
    printf("%u = ", num);
    for (i = 1; i <= 8; i++)
    {
        putchar((mask & num) ? '1' : '0');
        num <<= 1;
        if (i % 4 == 0) putchar(' ');
    }
    printf("\n");
}