特定年份和月份的星期六和星期日的数量

Question

使用Visual Basic .NET，如何查找特定年份和月份的星期六和星期日的数量？

Answer 1

我已经创建了一个使用计算方法来计算SATS和周日的功能。我还没有对它进行过测试。我已经在@ p.campbell的答案中测试了两者的性能以及计算方法（下面）和迭代方法，10,000次调用的结果以毫秒为单位。

计算：7 迭代：39

希望有所帮助。

戴夫

Dim month As Integer = 12 
    Dim year As Integer = 2011 

    'Calculate the Start and end of the month 
    Dim current As New DateTime(year, month, 1) 
    Dim ending As DateTime = current.AddMonths(1) 

    'Ints to hold the results 
    Dim numSat As Integer = 0 
    Dim numSun As Integer = 0 

    'Numbers used in the calculation 
    Dim dateDiff As Integer = (ending.Date - current.Date).Days 
    Dim firstDay As DayOfWeek = current.DayOfWeek 

    'Figure out how many whole weeks are in the month, there must be a Sat and Sunday in each 
    ' NOTE this is integer devision 
    numSat = dateDiff/7 
    numSun = dateDiff/7 

    'Calculate using the day of the week the 1st is and how many days over full weeks there are 
    ' NOTE the Sunday requires a bit extra as Sunday is value 0 and Saturday is value 6 
    numSat += If((firstDay + (dateDiff Mod 7)) > (DayOfWeek.Saturday), 1, 0) 
    numSun += If(((firstDay + (dateDiff Mod 7)) > (DayOfWeek.Saturday + 1)) Or (firstDay = DayOfWeek.Sunday And (dateDiff Mod 7 = 1)), 1, 0) 

    'Output the results 
    Console.WriteLine("Sats: " & numSat) 
    Console.WriteLine("Suns: " & numSun) 
    Console.ReadLine() 

Answer 2

试试这个：

• 采取月份和年份。
• 在DateTime中获得该月份/月份的第一个月份
• 找到该月份的“结束”，或者更确切地说，是下个月的开始。
• 循环并计算您的DayOfWeek的数量。

Dim month As Integer = 8 
Dim year As Integer = 2010 

Dim current As New DateTime(year, month, 1) 
Dim ending As DateTime = start.AddMonths(1) 

Dim numSat As Integer = 0 
Dim numSun As Integer = 0 

While current < ending 
    If current.DayOfWeek = DayOfWeek.Saturday Then 
     numSat += 1 
    End If 
    If current.DayOfWeek = DayOfWeek.Sunday Then 
     numSun += 1 
    End If 
    current = current.AddDays(1) 
End While 


Console.WriteLine("Sats: " & numSat) 
Console.WriteLine("Suns: " & numSun) 
Console.ReadLine()