c#實現輸出本月的月曆

格式要求：

複製代碼 代碼如下:SU MO TU WE TH FR SA
01 02 03 04
05 06 07 08 09 10 11
12 13 14 15 16 17 18
19 20 21 22 23 24 25
26 27 28 29 30

代碼：複製代碼 代碼如下: class Interview1
{
static void Main()
{
PrintCalender(2011, 10);
}
public static void PrintCalender(int year, int month)
{
formatDate fd = new formatDate(year, month);
string calender =
@"SU MO TU WE TH FR Sa
{0} {0} {0} {0} {0} {0} {0} {0}
{0} {0} {0} {0} {0} {0} {0} {0}
{0} {0} {0} {0} {0} {0} {0} {0}
{0} {0} {0} {0} {0} {0} {0} {0}
{0} {0} {0} {0} {0} {0} {0} {0}";

calender = string.Format(calender, fd).TrimEnd();
Console.WriteLine(calender);
}
}
class formatDate : IFormattable
{
int num;
int max;
public formatDate(int year, int month)
{
DateTime dt = new DateTime(year, month, 1);
num = (int)dt.DayOfWeek * -1;
max = DateTime.DaysInMonth(year, month);
}
public string ToString(string format,IFormatProvider formatProvider)
{
return num++ < 0 || num > max ? " " : num.ToString("00");
}
}