摘要:[VB6][VB.Net][C#][JAVA] 利用DateSerial 和 DateTime.IsLeapYear 判斷 平年 閏年 Leap Year
比較常使用潤年規則來判斷是否為潤年，如下
C# &JAVA：
private bool CheckLeap(int year)
{
if ((year % 4 == 0) && (year % 100 != 0) || (year % 400 == 0))
return true;
else return false;
}
VB：
Private Function JudgeLeap(ByVal intYear As Integer) As Boolean
If (intYear Mod 400 = 0) Or (intYear Mod 4 = 0 And intYear Mod 100 <> 0) Then
JudgeLeap = True
Else
JudgeLeap = False
End If
End Function
而微軟本身就已經提供好用的函數，程式設計者跟本不用寫落落長的判斷條件。
VB6&VBA：利用DateSerial可以回傳該年的月日，利用此功能來判定2月是否有29日，如果有29表示該年為潤年，MonthToLeapYear與IsLeap都是用來判斷是否有潤月
Private Sub Command1_Click()
Private
If MonthToLeapYear(Text1.Text) Then MsgBox Text1.Text & "年是閏年。" Else MsgBox Text1.Text & "不是閏年" If IsLeap(Text1.Text) Then MsgBox Text1.Text & "年是閏年。" Else MsgBox Text1.Text & "不是閏年"
End Sub
Private Function MonthToLeapYear(ByVal Yea As Integer) As Boolean
Private MonthToLeapYear = Day(DateSerial(Yea, 2, 29)) = 29End FunctionPrivate Function IsLeap(sYear As String) As Integer If IsDate("02/29/" & sYear) Then IsLeap = True Else IsLeap = False End If
End FunctionVB.Net：寫法稍有不同把Day換成VisualBasic.DateAndTime.Day
Public Class Form1 Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click If MonthToLeapYear(TextBox1.Text) Then MsgBox(TextBox1.Text & "年是閏年。") Else MsgBox(TextBox1.Text & "不是閏年") If IsLeap(TextBox1.Text) Then MsgBox(TextBox1.Text & "年是閏年。") Else MsgBox(TextBox1.Text & "不是閏年") End Sub Private Function MonthToLeapYear(ByVal Yea As Integer) As Boolean Return Microsoft.VisualBasic.DateAndTime.Day(DateSerial(Yea, 2, 29)) = 29 End Function Function IsLeap(ByVal sYear As String) As Boolean If IsDate("02/29/" & sYear) Then IsLeap = True Else IsLeap = False End If End FunctionEnd Class.NET Framework：DateTime.IsLeapYear 方法
利用DateTime.IsLeapYear 方法，來判斷是否為潤年。
private void button5_Click(object sender, EventArgs e) { string MyString = "2006-06-30"; DateTime MyDate = Convert.ToDateTime(MyString); string MyInfo = MyDate.Year + "年是："; if (DateTime.IsLeapYear(MyDate.Year)) { MyInfo += "潤年。"; } else { MyInfo += "平年。"; } MessageBox.Show(MyInfo, "信息提示", MessageBoxButtons.OK, MessageBoxIcon.Information); }
JAVA：利用Date類別判斷該年2月是否有29日
import java.util.*;class TAS { @SuppressWarnings("deprecation") public static void main(String[] args) { Date date = new Date(2000 , 2 , 0); System.out.println(date.getDate()); }} 利用Calendar.IsLeapYear 方法，來判斷是否為潤年。
http://java.sun.com/j2se/1.3/docs/api/java/util/GregorianCalendar.html
import java.util.*;import java.io.*;public class leapyear {/**
* @param args */ public static void main(String[] args) { // TODO Auto-generated method stub Calendar cal = Calendar.getInstance(); boolean booleanleapYear = ( (GregorianCalendar)cal ).isLeapYear(2008); if(booleanleapYear) { System.out.println(" is a leap year"); } else { System.out.println(" is Not a leap year"); } }}
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Microsoft MVP Award 2010~2017 C# 第四季
Microsoft MVP Award 2018~2022 .NET
