Finding difference and Comparing dates in VBA - vba

Question

I am trying to write a code that takes in a date as input and checks whether or not it is later than the date defined in the code.
Sub times()
Dim d1 As Date
n = Application.InputBox("Enter a date in mm/dd/yyyy format: ")
entered_date = CDate(entered_date)
d1 = 5 / 11 / 2021
If d1 > entered_date Then
d2 = DateDiff("D", d1, entered_date)
MsgBox ("late by " & d2)
Else
MsgBox ("on time")
End If
End Sub
the date diff function doesn't seem to be working for me or something is wrong my logic.
thanks in advance!

Answer 1

Well here is my answer. And as #NicholasHunter says, Option Explicit is always better!
It is clear that you figure it out, but consider this answer, anyway hope to help someone else.
Option Explicit
Sub times()
'Here you can validate the format date type for your system...
Dim SystemDateType As Integer
Dim SysFormatDate As String
' 0 = m-d-y
' 1 = d-m-y
' 2 = y-m-d
If Application.International(xlDateOrder) = 0 Then
SystemDateType = 0
SysFormatDate = "mm/dd/yyyy"
ElseIf Application.International(xlDateOrder) = 1 Then
SystemDateType = 1
SysFormatDate = "dd/mm/yyyy"
ElseIf Application.International(xlDateOrder) = 2 Then
SystemDateType = 2
SysFormatDate = "yyyy/mm/dd"
End If
'Of course you can do this:
'SystemDateType = Application.International(xlDateOrder)
'Or just use a Select Case...
'But just want to be clear and set the variable SysFormatDate
Dim StopedByUser As String: StopedByUser = "StopedByUser"
'Here you can define your own message.
Dim d1 As Date
'Look for the DateSerial function
Dim d2 As Variant
'This could be Long, but just want to set a data type
Dim ErrHandler As Integer
Dim n As Variant
'Or maybe String?
Dim entered_date As Date
'alwayes respect Data Types...
RetryInput:
n = Application.InputBox("Enter a date in " & SysFormatDate & " format: ")
'The user input...
'Cancel...
If n = False Then
MsgBox StopedByUser
End
End If
'Error Handler!
If IsDate(n) Then 'If the user input a real date...
entered_date = CDate(entered_date)
d1 = DateSerial(2011, 11, 16) ' ==> YYYY, MM, DD
'It is always better to use DateSerial!
'And hard coded... Well hope is just your for the question.
'd1 = 5 / 11 / 2021
If d1 >= entered_date Then
'The >= and <= are better in this case...
d2 = DateDiff("D", d1, entered_date)
MsgBox ("late by " & Abs(d2)) 'Abs return the absolute value, instead -321 return 321.
Else
MsgBox ("on time")
End If
Else 'If the user don't know what is a date...
'ask the user... want to try again...
ErrHandler = MsgBox("Please enter a formated date (" & SysFormatDate & ")", vbDefaultButton1 + vbYesNo, "Retry")
If ErrHandler = 7 Then '7 is NO
MsgBox StopedByUser
End
ElseIf ErrHandler = 6 Then '6 is YES and go back in the code to...
GoTo RetryInput
End If
'Check for MSGBOX here: https://learn.microsoft.com/en-us/office/vba/language/reference/user-interface-help/msgbox-function
End If
End Sub