GetDayName.cs

using System.Globalization;

namespace WeekOfDay
{
public static class GetDayName
{
//西暦年から曜日を求める
//（引　数）int 年,int 月,int 日
//（戻り値）string 曜日
//V2019.05.06
public static string getDayName(int year, int month, int day)
{
var culture = new CultureInfo("ja-JP");
DateTime date = new DateTime(year, month, day);
string str = culture.DateTimeFormat.GetDayName(date.DayOfWeek);
return str;
}
}
}