摸个鱼。。。

def bin1(num):
    if num==0:
        return 0
    if num==1:
        return 1
    a = num // 2
    b = num % 2
    return bin1(a)+bin1(b)



arr = range(0, 20)


for i in arr:
    a = f'{i:3d}'
    b = f'{i:08b}'
    def count1(bb):
        cnt = 0
        for ch in bb:
            if ch == '1':
                cnt+=1
        return cnt
    c = count1(b)
    d = bin1(i)
    print(f'{a} : {b} = {c:3d}  {"<-->" if c==d else "<xx>"} {d:2d}')