def count_bits(mut num: Int) -> Int:
result = 0
while num:
result += num % 2
num = num >> 1
return result
def count_bits2(mut num: Int) -> Int:
result = 0
while num:
result += num & 1
num >>= 1
return result
from std.testing import assert_equal
def main() raises:
num = 11
assert_equal(3, count_bits(num))
num = 128
assert_equal(1, count_bits(num))
num = 2147483645
assert_equal(30, count_bits(num))
num = 11
assert_equal(3, count_bits2(num))
num = 128
assert_equal(1, count_bits2(num))
num = 2147483645
assert_equal(30, count_bits2(num))