Private Sub Command1_Click()
    'PROGRAM D4R1
    'Driver for routine GAMMLN
    PI = 3.1415926
    Open "D:\VB常用數(shù)值算法集\DATA\FNCVAL.DAT" For Input As #1
    Do
      Line Input #1, Text$
    Loop While Text$ <> "Gamma Function"
    Line Input #1, NVAL$
    NVAL = Val(NVAL$)
       Print Text$
    Print
    Print "    X       Actual      GAMMA(X)"
    For I = 1 To NVAL
        Line Input #1, DUM$
        X = Val(Mid(DUM$, 1, 4))
        ACTUAL = Val(Mid(DUM$, 8))
        If X > 0 Then
            If X >= 1 Then
                CALC = GAMMLN(X)
            Else
                CALC = GAMMLN(X + 1) - Log(X)
            End If
            Print Tab(4); Format$(X, "#0.0#");
            Print Tab(12); Format$(Log(ACTUAL), "##.000000");
            Print Tab(25); Format$(CALC, "##.000000")
        End If
    Next I
    Close #1
End Sub