Check for integer input

Greetings everyone. I want to check with an if statement, if the user input is an integer or not. How do i do this? I 've tried the following:
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input = InputBox("Give an integer:")
If Int(input) = input Then
MsgMox "You gave an integer."
End If
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But, unfortunately this does not seem to work. Any idea? Thanks.

If VarType(input) = vbInteger Then MsgBox "You gave an integer."

Thanks a lot! for the quick answer.
 

59cobalt

If VarType(input) = vbInteger Then MsgBox "You gave an integer."

 
Though this seems to be another right way to check if the input is integer, i still don't get the right result
if i give integer as an input. check it for yourself! Any reason?

If VarType(input) = vbInteger Then MsgBox "You gave an integer."

By the way, the reason that the above way fails is different following this way. Now if is executed even
whem we give decimal numbers in the input. when we:

MsgBox VarType(input)

we take as a result the integer 8 in both cases that input is an integer or a decimal.
What's wrong anyway?

That's because InputBox() always returns either a string or Empty. You can use IsNumeric() to check if the string contains a numeric value. However, that will return True for doubles as well. Try this:

If IsNumeric(input) Then
 If CStr(CInt(input)) = input Then
 WScript.Echo "Input is an Integer."
 ElseIf CStr(CLng(input)) = input Then
 WScript.Echo "Input is a Long."
 ElseIf CStr(CDbl(input)) = input Then
 WScript.Echo "Input is a Double."
 End If
End If

Using InputBox() as your GUI is a bad idea. If you insist on communicating with your user via vanishing popups, you you should be aware of:

• InputBox() returns a string (vbString == 8) or an empty value (vbEmpty == 0) on abort
• the IsNumeric() functions checks whether a string can be converted to a value of numerical (sub) type; this conversion may loose info
• a numerical string can be converted to a double (CDbl()), a double may have no fractional part (double == Fix(double))
• a fixed double can be converted to a integral (sub) type: CByte(), CInt(), CLng() - if it is in the appropriate range

Here is a quick and dirty function that should handle most cases.
 

 
 Function IsInt(strIn) 
  Dim strFractional 
  if Not IsNumeric(strIn) Then 
  IsInt = False 
  Exit Function 
  End If 
  if InStr(strIn, ".") > 0 Then 
  strFractional = Split(strIn, ".")(1) 
  if CInt(strFractional) > 0 Then 
  IsInt = False 
  Exit Function 
  End If 
  End If 
  IsInt = True 
  End Function