对浮点数进行四舍五入处理的函数

英语不好， 见谅。

float myRound (float src, int idx)
{
    //move idx numbers right of the point
    //to the left
    for (int i = idx; i--;) {
        src *= 10;
    }

    //get left part of src
    float dest = static_cast<int>(src);
    
    //if the number behind the idx
    //are larger than 5, then article idx plus 1
    if (src >= dest + 0.5) {
        dest += 1;
    }

    //right nuber back to home
    for (int i = idx; i--;) {
        dest /= 10;
    }
    return std::move (dest);
}