Private Sub Command1_Click()
    'PROGRAM D4R21
    'Driver for routine BESSI0
    Open "D:\VB常用數值算法集\DATA\FNCVAL.DAT" For Input As #1
    Do
      Line Input #1, Text$
    Loop While Text$ <> "Modified Bessel Function I0"
    Line Input #1, NVAL$
    NVAL = Val(NVAL$)
    Print Text$
    Print
    Print "    X         Actual       BESSI0(X)"
    For I = 1 To NVAL
        Line Input #1, DUM$
        X = Val(Mid(DUM$, 1, 6))
        Value = Val(Mid(DUM$, 7))
        Print Tab(4); Format$(X, "#0.##");
        Print Tab(12); Format$(Value, ".0000000E+00");
        Print Tab(26); Format$(BESSI0(X), ".0000000E+00")
    Next I
    Close #1
End Sub