by John Anderson (2 Submissions)
Category: Miscellaneous
Compatability: Visual Basic 3.0
Difficulty: Unknown Difficulty
Date Added: Wed 3rd February 2021
Rating: 
(106 Votes)
Checks to see if a Credit Card Number is valid by performing the LUHN-10 check on it.
Inputs
CCNum as String
Code Returns
True if Valid, False if Invalid
Side Effects
May cause skin irritation
API Declarations
VBcodersPublic Function IsValidCCNum(CCNum As String) As Boolean
Dim i As Integer
Dim total As Integer
Dim TempMultiplier As String
For i = Len(CCNum) To 2 Step -2
total = total + CInt(Mid$(CCNum, i, 1))
TempMultiplier = CStr((Mid$(CCNum, i - 1, 1)) * 2)
total = total + CInt(Left$(TempMultiplier, 1))
If Len(TempMultiplier) > 1 Then total = total + CInt(Right$(TempMultiplier, 1))
Next
If Len(CCNum) Mod 2 = 1 Then total = total + CInt(Left$(CCNum, 1))
If total Mod 10 = 0 Then
IsValidCCNum = True
Else
IsValidCCNum = False
End If
End Function