algorithm Help Needed for 12hour clock

[RedGunner]

If lblHour.Text = TimeOfDay.Hour And lblMinute.Text = TimeOfDay.Minute And TimeOfDay.Second = 0 Then
msgbox("Alarm worked!")
End If

I had a 24 hour clock in which you can imagine the algorithm could be easily done by using two drop down boxes with values inside of it.

Hour: 1-24
Minute: 00-59

The labels contain what the user wants as the Alarm Set Time

However now I am wanting to make this into a 12 hour alarm clock, and I need some help on doing this.


I have now got 3 drop down boxes
Hour: 1-11
Minute: 00:59
AmPm: Choose Am or Pm


I am not looking for the code, I am just looking an algorithm to go along with so I can do this, I have spent all day trying to work what I could do, and I just can't do it... Thanks Guys!!

[Shaggy Hiker]

Show us some code. I personally don't see why you would have had more trouble with this when you were succesful with the other.

Also, though you didn't ask for anything about it, consider radio buttons for the AM vs PM. A combobox requires two selections, while the radio buttons require just one.

[RedGunner]

The code I showed you above was all I had...

[RedGunner]

[NickThissen]

Just add 12 hours when PM is selected?

[RedGunner]

        If cbAmPm.Text = "AM" Then
            If lblHour.Text = TimeOfDay.Hour And lblMinute.Text = TimeOfDay.Minute And TimeOfDay.Second = 0 Then
                startalarm()
            End If
        ElseIf cbAmPm.Text = "PM" Then
            If lblHour.Text + 12 = TimeOfDay.Hour And lblMinute.Text = TimeOfDay.Minute And TimeOfDay.Second = 0 Then
                startalarm()
            End If

Is this what you mean?

[RedGunner]

        If cbAmPm.Text = "AM" Then
            If lblHour.Text = TimeOfDay.Hour And lblMinute.Text = TimeOfDay.Minute And TimeOfDay.Second = 0 Then
                startalarm()
            End If
        ElseIf cbAmPm.Text = "PM" Then
            If lblHour.Text + 12 = TimeOfDay.Hour And lblMinute.Text = TimeOfDay.Minute And TimeOfDay.Second = 0 Then
                startalarm()
            End If
        End If

This works!! except for 12am and 12pm, this is really bugging me now lol... any ideas to fix?

[Shaggy Hiker]

The problem seems to be that time actually goes from 0-11, with 12 being used only because people don't really want to use 0. Unfortunately, this means that you have to deal with 12 as a special case. I don't see any good way around checking if lblHour.Text is 12, and setting it to 0 if it is. Of course, setting it to 0 might be a bit odd, since you don't have Option Strict ON, but you can still do it.

I'm a bit surprised that the code is working as is. Option Strict ON would give you an error when you are implicitly converting a string to an integer for the addition, but what surprises me is that the compiler is smart enough to convert the text to an integer and interpret the + operator as addition instead of leaving it as text and interpreting the + operator as concatenation.

[RedGunner]

yeah when i was typing it, i was waiting for an error but it did, and i do have option strict on too:S for another bit of code i have...

[Shaggy Hiker]

??? Is this 2008? That should have an error in 2005, since you are adding a string to an integer, but 2008, which I have not used, has type inference, which might let the compiler infer the type from the equals sign.

[jmcilhinney]

You could just use a DateTimePicker instead of ComboBoxes. That way you simply get its Value.TimeOfDay property and you're done.

[wy125]

does this work out for you?

    Public Function ConvertTo24Hour(ByVal hour As Integer, ByVal AM As Boolean) As Integer


        If AM Then
            Return hour Mod 12
        Else
            Return (hour Mod 12) + 12
        End If


    End Function

[dbasnett]

fyi - when using 24 hour clocks i don't think there is actually an hour 24. the sequence would be
23:58
23:59
00:00
00:01

and this If lblHour.Text = TimeOfDay.Hour, in 2008 with strict on causes an error.

[RedGunner]

Yeah exactly! So 24:00 would be 0am although the program won't know this.

I created this,

        If cbAmPm.Text = "AM" Then
            If lblHour.Text = 12 Then
                tempX = 0
                If tempX = TimeOfDay.Hour And lblMinute.Text = TimeOfDay.Minute And TimeOfDay.Second = 0 Then
                    startalarm()
                End If
            ElseIf lblHour.Text = TimeOfDay.Hour And lblMinute.Text = TimeOfDay.Minute And TimeOfDay.Second = 0 Then
                startalarm()
            End If
        End If
        If cbAmPm.Text = "PM" Then
            If lblHour.Text = 12 Then
                tempY = 12
                If tempY = TimeOfDay.Hour And lblMinute.Text = TimeOfDay.Minute And TimeOfDay.Second = 0 Then
                    startalarm()
                End If
            ElseIf lblHour.Text = TimeOfDay.Hour And lblMinute.Text = TimeOfDay.Minute And TimeOfDay.Second = 0 Then
                startalarm()
            End If
        End If

Great News! It worked and I tested it strictly with every possible scenario... Works a Charm!! thanks for the tip on +12

[wy125]

I think the code snippet I wrote does that unless I misunderstood the problem.