Function CRSpline1DA(XA As Variant, YA As Variant, XIA As Variant, Optional EndType As Long = 0, Optional Tension As Double = 0) As Variant
Dim CMResA() As Double, NumXRows As Long, NumXIrows As Long, i As Long, J As Long
Dim XAD() As Double, YAD() As Double, Rtn As Variant, Tbl() As Double
Dim C1 As Spline1DInterpolant

Rtn = GetSplineData(XA, YA, XAD, YAD, NumXRows, XIA, NumXIrows)

If Rtn <> 0 Then
CRSpline1DA = Rtn
Exit Function
End If

Spline1DBuildCatmullRom XAD, YAD, NumXRows, EndType, Tension, C1

ReDim CMResA(1 To NumXIrows, 1 To 1)
For i = 1 To NumXIrows
CMResA(i, 1) = Spline1DCalc(C1, XIA(i, 1))
Next i

CRSpline1DA = CMResA

End Function

   // Input objects
   ap::real_1d_array xValues;
   ap::real_1d_array yValues;
   int numberOfValues = 56;
   xValues.setcontent(0, numberOfValues, xDoubles);
   yValues.setcontent(0, numberOfValues, yDoubles);

   spline1dinterpolant interpolant; // Return object
   spline1dbuildcatmullrom(xValues, yValues, numberOfValues, 0, 0.1, interpolant);