16

#主要是考虑边界情况
def power(base, exponent):
    if base == 0 and exponent < 0:
        return 0

    absexponent = exponent
    if exponent < 0:
        absexponent = -exponent

    result = powerWithExponent(base, absexponent)
    if exponent < 0:
        return 1 / result
    return result


def powerWithExponent(base, exponent):
    result = 1.0
    for i in range(exponent):
        result *= base

    return result


print(power(1.2, -2))