通过日期获取星期

/// <summary>根据日期，获得星期几</summary>
/// <param name="y">年</param>
/// <param name="m">月</param>
/// <param name="d">日</param>
/// <returns>星期几，1代表星期一；7代表星期日</returns>
public static int getWeekDay(int y, int m, int d)
{
    if (m == 1) m = 13;
    if (m == 2) m = 14;
    int week = (d + 2 * m + 3 * (m + 1) / 5 + y + y / 4 - y / 100 + y / 400) % 7 + 1;
    return week;
}
public static string GetWeekDay(int y,int m,int d)
{
    int weeks = getWeekDay(y, m, d);
    switch (weeks)
    {
        case 1:
            return "星期一";
        case 2:
            return "星期二";
        case 3:
            return "星期三";
        case 4:
            return "星期四";
        case 5:
            return "星期五";
        case 6:
            return "星期六";
        case 7:
            return "星期日";
    }
    return "";
}