[RESOLVED]Need help coding from date to num and back again

[Stimpson]

Its late and this is killing me nothing major or detrimental just working on some code and its kicking my rump. Any help is appreciated.

Here is the goal. to take a string in the format "##/##/####" and convert it into an integer. 1/1/1 being equal to 1 and 1/2/1 equal to 2 and 12/31/1 equal to 365. leap year is accounted for every year that is divisable by 4 but not divisible by 100 unless it is also divisible by 400.

ok that sai d i want to be able to reverse that code and convert the number back into a date. So i should be able to add 5 to the number and get a date 5 days from now. i am almost there however if you put in 12/31/2005 and add 1 you get 12/32/2005 I have looked over it and cant find my error.

Thanks in advance if you find my mistake

the functions are datetonum(byval str1 as string) and numtodate(byval num1 as integer)

here is the code

Function datetonum(ByVal str1 As String)
 
        Dim length As Integer
        Dim noofdays As String
        Dim char1 As Char
        Dim marker As Integer = 1
        Dim month As String = ""
        Dim day As String = ""
        Dim year As String = ""
        Dim leap As Boolean = False
 
 
 
 
 
        length = Len(str1)
 
        For i As Integer = 1 To length
            char1 = Mid(str1, i, 1)
            If char1 = "/" Then
                marker = marker + 1
            Else
                If marker = 1 Then
                    month = month & char1
                End If
                If marker = 2 Then
                    day = day & char1
                End If
                If marker = 3 Then
                    year = year & char1
                End If
            End If
        Next
        If month <= 9 Then
            month = "0" & month
        End If
        If day <= 9 Then
            day = "0" & day
        End If
        year = Mid(year, 1, 4)
 
 
 
 
        noofdays = day + monthtodays(month, year) + yearstodays(year)
 
        Return noofdays
 
 
    End Function
 
    Function yearstodays(ByVal num1 As Integer)
        Dim years As Integer
        Dim leap As Boolean = False
        Dim days As Integer = 0
 
 
 
        Do While years < num1 - 1
            If years Mod 4 = 0 And years > 3 Then
                If Not years Mod 100 = 0 Then
                    leap = True
                Else
                    If years Mod 400 = 0 Then
                        leap = True
                    End If
                End If
            End If
 
            If leap Then
                days = days + 366
            Else
                days = days + 365
            End If
            years = years + 1
        Loop
 
 
 
 
        Return days
 
    End Function
 
    Function monthtodays(ByVal num1 As Integer, ByVal year As Integer)
        Dim month As Integer
        Dim leap As Boolean = False
        Dim days As Integer = 0
 
        For month = 0 To num1 - 1
            If year Mod 4 = 0 And year > 3 Then
                If Not year Mod 100 = 0 Then
                    leap = True
                Else
                    If year Mod 400 = 0 Then
                        leap = True
                    End If
                End If
            End If
 
            If month = 4 Or month = 6 Or month = 9 Or month = 11 Then
                days = days + 30
            End If
            If month = 2 Then
                If leap Then
                    days = days + 29
                Else
                    days = days + 28
                End If
            End If
            If month = 1 Or month = 3 Or month = 5 Or month = 7 Or month = 8 Or month = 10 Or month = 12 Then
                days = days + 31
            End If
        Next month
 
        Return days
 
    End Function
 
 
    Function numtodate(ByVal int1 As Integer)
 
        Dim year As String
        Dim month As Integer = 1
        Dim days As Integer = 1
        Dim test As Integer = int1
        Dim leap As Boolean = False
        Dim returndate As String
 
 
        year = findyear(int1)
        month = findmonth(int1 - datetonum("1/1/" & year))
        days = int1 - (datetonum(month & "/1/" & year)) + 1
 
        If month <= 9 Then
            month = "0" & month
        End If
        If days <= 9 Then
            days = "0" & days
        End If
        year = Mid(year, 1, 4)
 
        returndate = month & "/" & days & "/" & year
 
        Return returndate
 
    End Function
 
    Function findyear(ByVal int1 As Integer)
        Dim year As Integer = 1
        Dim month As Integer = 1
        Dim days As Integer = 1
        Dim test As Integer = int1
        Dim leap As Boolean = False
 
        While (test > 365 And leap = False) Or (test > 366 And leap = True)
 
 
            If year Mod 4 = 0 And year > 3 Then
                If Not year Mod 100 = 0 Then
                    leap = True
                Else
                    If year Mod 400 = 0 Then
                        leap = True
                    End If
                End If
            End If
            If leap = True Then
                test = test - 366
            Else
                test = test - 365
            End If
            year = year + 1
 
        End While
 
        Return year
 
    End Function
 
    Function findmonth(ByVal int1 As Integer)
        Dim year As Integer = 1
        Dim month As Integer = 1
        Dim days As Integer = 1
        Dim test As Integer = int1
        Dim leap As Boolean = False
        While test > 31
            If month = 4 Or month = 6 Or month = 9 Or month = 11 Then
                test = test - 30
            End If
            If month = 2 Then
                If leap Then
                    test = test - 29
                Else
                    test = test - 28
                End If
            End If
            If month = 1 Or month = 3 Or month = 5 Or month = 7 Or month = 8 Or month = 10 Or month = 12 Then
                test = test - 31
            End If
            month = month + 1
        End While
 
        Return month
    End Function

[gigemboy]

The DateTime class has a handy .DayOfYear property, and you can parse your string right into it Try the code below:

Dim MyDate As String = "12/31/2005"
        Dim DateNow As DateTime
        DateNow = Date.Parse(MyDate)
        MsgBox(DateNow.DayOfYear.ToString) 'displays "365"

A lot less code It takes leap years into account as well, you don't have to worry about it. There are also properties to display just the month, etc.. lots of things you can do with the class...

***EDIT - there is also an .AddDays method that can add the number of days you want, as stated in your above post.. the code below adds one day to the above code..

Dim MyDate As String = "12/31/2005"
        Dim DateNow As DateTime
        DateNow = Date.Parse(MyDate)
        DateNow = DateNow.AddDays(1)
        MsgBox(DateNow.DayOfYear.ToString) 'displays "1", since it will be 01/01/2006

[Stimpson]

if i use that how do i go back from the number to the date? and what if the date is 2 years ago?

thanks for the reply

[gigemboy]

The date being two years ago won't matter at all, notice I just passed in a string that was in the format of a date. You can put any date you want and it will work. To go back, there are methods from the same datetime class (reading up on the class and its methods might be helpful ) You will notice that there is a .ToShortDateString that will convert it back with one line of code, so now adding it to the above code:

Dim MyDate As String = "12/31/2005"
        Dim DateNow As DateTime
        DateNow = Date.Parse(MyDate)
        MsgBox(DateNow.DayOfYear.ToString) 'displays "365"
        Dim DateToString As String
        DateToString = DateNow.ToShortDateString 'converts it back to the original date
        MsgBox(DateToString) 'displays the original "12/31/2005" string

[Stimpson]

thanks very much.

however i woke up this morning in a do or die mood and came up with the solution. I am posting my code here for anyone interested just in case it might help someone else.

Riley Belile

Function datetonum(ByVal str1 As String)
        Dim length As Integer
        Dim str2 As String
        Dim char1 As Char
        Dim marker As Integer = 1
        Dim month As String
        Dim day As String
        Dim year As String
        Dim num1 As Integer
        Dim num2 As Integer
 
 
 
 
 
        length = Len(str1)
 
        For i As Integer = 1 To length
            char1 = Mid(str1, i, 1)
            If char1 = "/" Then
                marker = marker + 1
            Else
                If marker = 1 Then
                    month = month & char1
                End If
                If marker = 2 Then
                    day = day & char1
                End If
                If marker = 3 Then
                    year = year & char1
                End If
            End If
        Next
        If month <= 9 Then
            month = "0" & month
        End If
        If day <= 9 Then
            day = "0" & day
        End If
        year = Mid(year, 1, 4)
 
 
        num1 = day + monthtodays(month, year) + yearstodays(year)
 
 
        Return num1
 
 
    End Function
 
 
    Function yearstodays(ByVal num1 As Integer)
        Dim years As Integer = 1
        Dim leap As Boolean = False
        Dim days As Integer = 0
        Dim test As Integer
 
 
 
        Do While years <= num1
            leap = False
            test = years Mod 4
            If years Mod 4 = 0 And years > 3 Then
                If Not years Mod 100 = 0 Then
                    leap = True
                Else
                    If years Mod 400 = 0 Then
                        leap = True
                    Else
                        leap = False
                    End If
                End If
            End If
 
            If leap Then
                days = days + 366
            Else
                days = days + 365
            End If
            years = years + 1
        Loop
 
 
 
 
        Return days - 365
 
 
 
    End Function
 
    Function monthtodays(ByVal num1 As Integer, ByVal year As String)
 
        Dim leap As Boolean
 
 
 
 
        If year Mod 4 = 0 And year > 3 Then
            If Not year Mod 100 = 0 Then
                leap = True
            Else
                If year Mod 400 = 0 Then
                    leap = True
                End If
            End If
        End If
 
        If leap = False Then
 
            Select Case (num1)
                Case 1 ' jan
                    Return 0
                Case 2 'feb
                    Return 31 ' for jan
                Case 3 'mar
                    Return 28 + 31 'for jan and feb
                Case 4 'apr
                    Return 31 + 28 + 31
                Case 5 'may
                    Return 31 + 28 + 31 + 30
                Case 6 'june
                    Return 31 + 28 + 31 + 30 + 31
                Case 7 'july
                    Return 31 + 28 + 31 + 30 + 31 + 30
                Case 8 'aug
                    Return 31 + 28 + 31 + 30 + 31 + 30 + 31
                Case 9 'sep
                    Return 31 + 28 + 31 + 30 + 31 + 30 + 31 + 31
                Case 10 'oct
                    Return 31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30
                Case 11 'nov
                    Return 31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31
                Case 12 'dec
                    Return 31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30
            End Select
 
 
        Else 'leap is true
            Select Case (num1)
                Case 1 ' jan
                    Return 0
                Case 2 'feb
                    Return 31
                Case 3 'mar
                    Return 31 + 29
                Case 4 'apr
                    Return 31 + 29 + 31
                Case 5 'may
                    Return 31 + 29 + 31 + 30
                Case 6 'june
                    Return 31 + 29 + 31 + 30 + 31
                Case 7 'july
                    Return 31 + 29 + 31 + 30 + 31 + 30
                Case 8 'aug
                    Return 31 + 29 + 31 + 30 + 31 + 30 + 31
                Case 9 'sep
                    Return 31 + 29 + 31 + 30 + 31 + 30 + 31 + 31
                Case 10 'oct
                    Return 31 + 29 + 31 + 30 + 31 + 30 + 31 + 31 + 30
                Case 11 'nov
                    Return 31 + 29 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31
                Case 12 'dec
                    Return 31 + 29 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30
            End Select
        End If
 
 
 
    End Function
 
 
 
    Function numtodate(ByVal int1 As Integer)
 
        Dim year As String
        Dim month As Integer = 1
        Dim days As Integer = 1
        Dim test As Integer = int1
        Dim leap As Boolean = False
        Dim returndate As String
 
 
        year = findyear(int1)
        month = findmonth(int1 - yearstodays(year), year)
        days = int1 - monthtodays(month, year) - yearstodays(year)
 
        If month <= 9 Then
            month = "0" & month
        End If
        If days <= 9 Then
            days = "0" & days
        End If
        year = Mid(year, 1, 4)
 
        returndate = month & "/" & days & "/" & year
 
        Return returndate
 
    End Function
 
    Function findyear(ByVal int1 As Integer)
        Dim year As Integer = 1
        Dim averageyear As Double = 365.2425
 
        year = Math.Floor((int1 + 365.0) / averageyear)
 
        Return year
 
    End Function
 
 
    Function findmonth(ByVal int1 As Integer, ByVal years As Integer)
 
        Dim leap As Boolean = False
        Dim count1 As Integer
        Dim test As Integer
        Dim month As Integer
 
 
        If years Mod 4 = 0 And years > 3 Then
            If Not years Mod 100 = 0 Then
                leap = True
            Else
                If years Mod 400 = 0 Then
                    leap = True
                Else
                    leap = False
                End If
            End If
        End If
 
 
        For count1 = 1 To 12
            If leap = False Then
                Select Case (count1)
                    Case 1 ' jan
                        test = 0
                    Case 2 'feb
                        test = 31 ' for jan
                    Case 3 'mar
                        test = 28 + 31 'for jan and feb
                    Case 4 'apr
                        test = 31 + 28 + 31
                    Case 5 'may
                        test = 31 + 28 + 31 + 30
                    Case 6 'june
                        test = 31 + 28 + 31 + 30 + 31
                    Case 7 'july
                        test = 31 + 28 + 31 + 30 + 31 + 30
                    Case 8 'aug
                        test = 31 + 28 + 31 + 30 + 31 + 30 + 31
                    Case 9 'sep
                        test = 31 + 28 + 31 + 30 + 31 + 30 + 31 + 31
                    Case 10 'oct
                        test = 31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30
                    Case 11 'nov
                        test = 31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31
                    Case 12 'dec
                        test = 31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30
                End Select
            Else 'leap is true
                Select Case (count1)
                    Case 1 ' jan
                        test = 0
                    Case 2 'feb
                        test = 31
                    Case 3 'mar
                        test = 31 + 29
                    Case 4 'apr
                        test = 31 + 29 + 31
                    Case 5 'may
                        test = 31 + 29 + 31 + 30
                    Case 6 'june
                        test = 31 + 29 + 31 + 30 + 31
                    Case 7 'july
                        test = 31 + 29 + 31 + 30 + 31 + 30
                    Case 8 'aug
                        test = 31 + 29 + 31 + 30 + 31 + 30 + 31
                    Case 9 'sep
                        test = 31 + 29 + 31 + 30 + 31 + 30 + 31 + 31
                    Case 10 'oct
                        test = 31 + 29 + 31 + 30 + 31 + 30 + 31 + 31 + 30
                    Case 11 'nov
                        test = 31 + 29 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31
                    Case 12 'dec
                        test = 31 + 29 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30
                End Select
            End If
            If int1 > test Then
 
                month = count1
 
            End If
        Next count1
 
        Return month
    End Function

I love this forum

[gigemboy]

Well congrats on getting it I know its a lot more code, but sometimes when you spend enough time on something and finally get it to work, you are more inclined to use it, even if there is a much shorter way...