Data commit

Task/Cumulative-standard-deviation/Visual-Basic/cumulative-standard-deviation.vb

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+Function avg(what() As Variant) As Variant
+    'treats non-numeric strings as zero
+    Dim L0 As Variant, total As Variant
+    For L0 = LBound(what) To UBound(what)
+        If IsNumeric(what(L0)) Then total = total + what(L0)
+    Next
+    avg = total / (1 + UBound(what) - LBound(what))
+End Function
+
+Function standardDeviation(fp As Variant) As Variant
+    Static list() As Variant
+    Dim av As Variant, tmp As Variant, L0 As Variant
+
+    'add to sequence if numeric
+    If IsNumeric(fp) Then
+        On Error GoTo makeArr   'catch undimensioned list
+        ReDim Preserve list(UBound(list) + 1)
+        On Error GoTo 0
+        list(UBound(list)) = fp
+    End If
+
+    'get average
+    av = avg(list())
+
+    'the actual work
+    For L0 = 0 To UBound(list)
+        tmp = tmp + ((list(L0) - av) ^ 2)
+    Next
+    tmp = Sqr(tmp / (UBound(list) + 1))
+
+    standardDeviation = tmp
+
+    Exit Function
+makeArr:
+    If 9 = Err.Number Then
+        ReDim list(0)
+    Else
+        'something's wrong
+        Err.Raise Err.Number
+    End If
+    Resume Next
+End Function
+
+Sub tester()
+    Dim x As Variant
+    x = Array(2, 4, 4, 4, 5, 5, 7, 9)
+    For L0 = 0 To UBound(x)
+        Debug.Print standardDeviation(x(L0))
+    Next
+End Sub