用.NET语言写出计算股票技术指标BRAR，总共两个参数，第一个参数为datatable类型，第二个参数为int型，返回值为datatable类型，double类型全部四舍五入保留3位小数，请写好函数和参数的详细注释。

以下是用.NET语言编写计算股票技术指标BRAR的函数：

/// <summary>
/// 计算股票技术指标BRAR
/// </summary>
/// <param name="data">数据表</param>
/// <param name="n">周期</param>
/// <returns>计算结果表</returns>
public static DataTable CalculateBRAR(DataTable data, int n)
{
    DataTable result = new DataTable();
    result.Columns.Add("BR", typeof(double));
    result.Columns.Add("AR", typeof(double));

    if (data.Rows.Count < n)
    {
        return result;
    }

    double[] br = new double[data.Rows.Count];
    double[] ar = new double[data.Rows.Count];

    double[] high = new double[n];
    double[] low = new double[n];

    double sum_br = 0;
    double sum_ar = 0;

    for (int i = 0; i < data.Rows.Count; i++)
    {
        double close = Convert.ToDouble(data.Rows[i]["close"]);
        double open = Convert.ToDouble(data.Rows[i]["open"]);
        double high_price = Convert.ToDouble(data.Rows[i]["high"]);
        double low_price = Convert.ToDouble(data.Rows[i]["low"]);

        if (i < n)
        {
            high[i] = high_price;
            low[i] = low_price;
        }
        else
        {
            double sum_high = 0;
            double sum_low = 0;

            for (int j = i - n; j < i; j++)
            {
                sum_high += Convert.ToDouble(data.Rows[j]["high"]);
                sum_low += Convert.ToDouble(data.Rows[j]["low"]);
            }

            high[i % n] = high_price;
            low[i % n] = low_price;

            double br_value = (sum_high - sum_low) / (n * sum_high + n * sum_low) * 100;
            double ar_value = (high_price - open) / (open - low_price) * 100;

            sum_br += br_value;
            sum_ar += ar_value;

            br[i] = sum_br / n;
            ar[i] = sum_ar / n;
        }

        DataRow row = result.NewRow();
        row["BR"] = Math.Round(br[i], 3);
        row["AR"] = Math.Round(ar[i], 3);
        result.Rows.Add(row);
    }

    return result;
}

其中，参数`data`为数据表，包含以下列：`close`为收盘价，`open`为开盘价，`high`为最高价，`low`为最低价。参数`n`为周期，表示计算BRAR指标的天数。返回值为计算结果表，包含两列：`BR`为BR指标值，`AR`为AR指标值。