GetTimeNow



  • Been working on a date related bug in a monitoring app that I'm maintaining  (dates being passed around as strings, different code assumes different formats, when the date is ambiguous bad things happen) and came across this:

        Function getTimeNow()

            Dim hour As String = String.Empty
            Dim min As String = String.Empty

            'set the hour in the correct format
            If Date.Now.Hour < 10 Then
                'add a 0 in the front
                hour = "0" & Date.Now.Hour
            Else
                hour = Date.Now.Hour
            End If

            'set the min in the correct format
            If Date.Now.Minute < 10 Then
                'add a 0 in the front
                min = "0" & Date.Now.Minute
            Else
                min = Date.Now.Minute
            End If

            Return hour & ":" & min & ":00"

        End Function

     
    Any reason why this is better than Date.Now.ToString("hh:mm") & ":00" ? None that I can see... good thing this function is never called then...



  • I don't know the details, but maybe one format goes from 1 to 12 and the other from 0 to 23?

    You need to be careful if you keep polling the current time, if the hour or minute increment mid-function you could get e.g. 010:00:00 when hour goes from 9 to 10, or 05:010:00, when minute goes from 9 to 10, or 04:00:00 at either side of 5 o'clock

    Better to store Date.Now at the start and work on that.

    Ian.



  • There's a very good reason for it. I believe it's called "Not Invented Here". Why use a single line of code when you can waste hours creating drivel like this?

     



  • I always "like" the way these guys comparing a volatile variable with a constant value and then conditionally use the volatile variable:

            If Date.Now.Minute < 10 Then
                'add a 0 in the front
                min = "0" & Date.Now.Minute
            Else
                min = Date.Now.Minute
            End If

    should be

            minutes = Date.Now.Minute
            If  minutes < 10 Then

                'add a 0 in the front

                min = "0" & minutes

            Else

                min = minutes

            End If

    so the Date.Now.Minute does not change between the test for < 10 and the next statement where it is read again. okok, the window of opportunity is really small, but it is there.

    but the best solution IMHO is still this: 

    minutes =  Date.Now.Minute
    min = right$("0" & minutes,2)

     



  • Are you sure we're not working on the same project?  The only thing that would indicate otherwise is the lack of a fully-commented Try, (empty) Catch, (empty) Finally construct.



  • This vb code is hurting my eyes !



  • "This vb code is hurting my eyes !"

    The appearance of the code is remarkably sane for vb code.  Variables are declared with types, and the if/else structure is very readable.  The fact that they want to encapsulate the functionality provided by Date.Now.ToString("hh:mm") & ":00" isn't a big deal either.  If you do this a lot it's nice to have that small bit a logic scurried away somewhere.  But the fact that they took 20 lines to implement a one-liner, the volatile variable bug, and the fact that the function exists but is never used make this wtf-worthy.



  • A reason why it is worse.

    If Date.Now.Hour < 10 Then
                'add a 0 in the front
                hour = "0" & Date.Now.Hour

     

    When the first Date.Now.Hour returns 9:59:59.999999999 then the result will be 010:00:00.

    Unlikely, but not impossible.
     

     

     



  • @blupp said:

    I always "like" the way these guys comparing a volatile variable with a constant value and then conditionally use the volatile variable:

            If Date.Now.Minute < 10 Then
                'add a 0 in the front
                min = "0" & Date.Now.Minute
            Else
                min = Date.Now.Minute
            End If

    should be

            minutes = Date.Now.Minute
            If  minutes < 10 Then

                'add a 0 in the front

                min = "0" & minutes

            Else

                min = minutes

            End If

    so the Date.Now.Minute does not change between the test for < 10 and the next statement where it is read again. okok, the window of opportunity is really small, but it is there.

     

    I "like" how your solution has the same problem as the original.

        hour = Date.Now.Hour   'Yields 5 on 5:59:59.999

        minute = Date.Now.Minute 'Yields 0 on 6:00:00.000


     



  • @JvdL said:

    I "like" how your solution has the same problem as the original.

        hour = Date.Now.Hour   'Yields 5 on 5:59:59.999

        minute = Date.Now.Minute 'Yields 0 on 6:00:00.000

    And you are right indeed!  but it was good enough for an example :-)

     



  • @jcoehoorn said:

    The appearance of the code is remarkably sane for vb code.  Variables are declared with types, and the if/else structure is very readable.  The fact that they want to encapsulate the functionality provided by Date.Now.ToString("hh:mm") & ":00" isn't a big deal either.  If you do this a lot it's nice to have that small bit a logic scurried away somewhere.  But the fact that they took 20 lines to implement a one-liner, the volatile variable bug, and the fact that the function exists but is never used make this wtf-worthy.

    Can't you do Date.Now.ToString("hh:mm:00") ?


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