Private Sub Command1_Click()
    'PROGRAM D12R7
    'Driver for routine CORREL
    N = 64
    N2 = 128
    PI = 3.1415926
    Dim DATA1(64), DATA2(64), ANS(128)
    For I = 1 To N
        DATA1(I) = 0#
        If I > (N / 2 - N / 8) And I < (N / 2 + N / 8) Then
            DATA1(I) = 1#
        End If
        DATA2(I) = DATA1(I)
    Next I
    Call CORREL(DATA1(), DATA2(), N, ANS())
    'Caculate directly
    Print
    Print Tab(5); " n          CORREL     Direct Calc"
    For I = 0 To 16
        CMP = 0#
        For J = 1 To N
            CMP = CMP + DATA1(((I + J - 1) Mod N) + 1) * DATA2(J)
        Next J
        Print Tab(5); I, Format$(ANS(I + 1), "##.#####0"),
        Print Format$(CMP, "##.#####0")
    Next I
End Sub