C/C++实现四舍五入保留指定小数位

C/C++实现四舍五入保留指定小数位

number：传入的原始数
bits：小数点后保留的维数

double round(double number, unsigned int bits) {
    LL integerPart = number;
    number -= integerPart;
    for (unsigned int i = 0; i < bits; ++i)
        number *= 10;
    number = (LL) (number + 0.5);
    for (unsigned int i = 0; i < bits; ++i)
        number /= 10;
    return integerPart + number;
}

尴尬的是，最后发现printf会自动四舍五入