Private Sub Command1_Click()
    'PROGRAM D2R2
    'DRIVER for routine RATINT
    NPT = 6
    Dim X(6), Y(6)
    For I = 1 To NPT
        X(I) = I * 2# / NPT
        Y(I) = FUNC(X(I))
    Next I
    Print
    Print Tab(5); "Diagonal rational function interpolation"
    Print Tab(5); " x       interap.    accuracy       actual"
    For I = 1 To 10
        XX = 0.2 * I
        Call RATINT(X(), Y(), NPT, XX, YY, DYY)
        YEXP = FUNC(XX)
        Print Tab(5); Format$(XX, "#.#0");
        Print Tab(13); Format$(YY, ".####00");
        Print Tab(25); Format$(DYY, ".0000E+00");
        Print Tab(40); Format$(YEXP, ".######")
    Next I
End Sub
Function FUNC(X)
    FUNC = X * Exp(-X) / ((X - 1#) ^ 2 + 1#)
End Function