Data commit

Task/Increment-a-numerical-string/VBA/increment-a-numerical-string-1.vba

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+Public Function incr(astring As String) As String
+'simple function to increment a number string
+   incr = CStr(CLng(astring) + 1)
+End Function

Task/Increment-a-numerical-string/VBA/increment-a-numerical-string-2.vba

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+Public Function Lincr(astring As String) As String
+'increment a number string, of whatever length
+'calls function "increment" or "decrement"
+Dim result As String
+
+'see if it is a negative number
+If left$(astring, 1) = "-" Then
+  'negative x: decrease |x| by 1, then add "-"
+  '(except if the result is zero)
+  result = decrement(Mid$(astring, 2))
+  If result <> "0" Then result = "-" & result
+Else
+  '0 or positive x: increase x by 1
+  If left$(astring, 1) = "+" Then  'allow a + before the number
+    result = increment(Mid$(astring, 2))
+  Else
+    result = increment(astring)
+  End If
+End If
+Lincr = result
+End Function
+
+Public Function increment(astring) As String
+Dim result As String
+'increment a string representing a positive number
+'does not work with negative numbers
+carry = 1
+L = Len(astring)
+result = ""
+For j = L To 1 Step -1
+  digit = Val(Mid$(astring, j, 1)) + carry
+  If digit > 9 Then
+    digit = digit - 10
+    carry = 1
+  Else
+    carry = 0
+  End If
+  result = CStr(digit) & result
+Next
+If carry = 1 Then result = CStr(carry) & result
+increment = result
+End Function
+
+Public Function decrement(astring) As String
+Dim result As String
+'decrement a string representing a positive number
+'does not work with zero or negative numbers
+borrow = 1
+L = Len(astring)
+result = ""
+For j = L To 1 Step -1
+  digit = Val(Mid$(astring, j, 1)) - borrow
+  If digit < 0 Then
+    digit = digit + 10
+    borrow = 1
+  Else
+    borrow = 0
+  End If
+  result = CStr(digit) & result
+Next
+'remove leading zero, if necessary
+If (Len(result) > 1) And (left$(result, 1) = "0") Then result = Mid$(result, 2)
+decrement = result
+End Function