Private Sub Command1_Click()
    'PROGRAM D4R19
    'Driver for routine BESSY
    Open "D:\VB常用數值算法集\DATA\FNCVAL.DAT" For Input As #1
    Do
      Line Input #1, Text$
      Text$ = Left(Text$, 18)
    Loop While Text$ <> "Bessel Function Yn"
    Line Input #1, NVAL$
    NVAL = Val(NVAL$)
    Print Text$
    Print
    Print "   N      X         Actual         BESSY(N,X)"
    For I = 1 To NVAL
        Line Input #1, DUM$
        N = Val(Mid(DUM$, 1, 6))
        X = Val(Mid(DUM$, 7, 6))
        Value = Val(Mid(DUM$, 13))
        Print Tab(4); Format$(N, "#0");
        Print Tab(10); Format$(X, "#0.0#");
        Print Tab(18); Format$(Value, ".000000E+00");
        Print Tab(34); Format$(BESSY(N, X), ".000000E+00")
    Next I
    Close #1
End Sub