Data commit

Task/Validate-International-Securities-Identification-Number/FreeBASIC/validate-international-securities-identification-number.basic

@@ -0,0 +1,78 @@
+' version 27-10-2016
+' compile with: fbc -s console
+
+#Ifndef TRUE        ' define true and false for older freebasic versions
+    #Define FALSE 0
+    #Define TRUE Not FALSE
+#EndIf
+
+Function luhntest(cardnr As String) As Long
+
+    cardnr = Trim(cardnr) ' remove spaces
+
+    Dim As String reverse_nr = cardnr
+    Dim As Long i, j, s1, s2, l = Len(cardnr) -1
+
+    ' reverse string
+    For i = 0 To l
+        reverse_nr[i] = cardnr[l - i]
+    Next
+    ' sum odd numbers
+    For i = 0 To l Step 2
+        s1 = s1 + (reverse_nr[i] - Asc("0"))
+    Next
+    ' sum even numbers
+    For i = 1 To l Step 2
+        j = reverse_nr[i] - Asc("0")
+        j = j * 2
+        If j > 9 Then j = j Mod 10 +1
+        s2 = s2 + j
+    Next
+
+    If (s1 + s2) Mod 10 = 0 Then
+        Return TRUE
+    Else
+        Return FALSE
+    End If
+
+End Function
+
+' ------=< MAIN >=-----
+
+Dim As String test_str
+Dim As String test_set(1 To ...) = { "US0378331005", "US0373831005", _
+                    "U50378331005", "US03378331005", "AU0000XVGZA3", _
+                                     "AU0000VXGZA3", "FR0000988040" }
+
+Dim As Long i, l, n, x
+
+For i = 1 To UBound(test_set)
+    test_str = ""
+    l = Len(test_set(i))
+    If l <> 12 Then
+        Print test_set(i), "Invalid, length <> 12 char."
+        Continue For
+    End If
+    If test_set(i)[0] < Asc("A") Or test_set(i)[1] < Asc("A") Then
+        Print test_set(i), "Invalid, number needs to start with 2 characters"
+        Continue For
+    End If
+    For n = 0 To l -1
+        x = test_set(i)[n] - Asc("0")
+        ' if test_set(i)[i] is a letter we to correct for that
+        If x > 9 Then x = x -7
+        If x < 10 Then
+            test_str = test_str + Str(x)
+        Else ' two digest number
+            test_str = test_str + Str(x \ 10) + Str(x Mod 10)
+        End If
+    Next
+    Print test_set(i), IIf(luhntest(test_str) = TRUE, "Valid","Invalid, checksum error")
+Next
+
+
+' empty keyboard buffer
+While InKey <> "" : Wend
+Print : Print "hit any key to end program"
+Sleep
+End