常用的数值算法的VB程序

				Function RTBIS(X1, X2, XACC)
				    JMAX = 40
				    FMID = FUNC(X2)
				    F = FUNC(X1)
				    If F * FMID >= 0# Then
				        Print "Root must be bracketed for bisection."
				    End If
				    If F < 0# Then
				        RTBIS = X1
				        DX = X2 - X1
				    Else
				        RTBIS = X2
				        DX = X1 - X2
				    End If
				    For J = 1 To JMAX
				        DX = DX * 0.5
				        XMID = RTBIS + DX
				        FMID = FUNC(XMID)
				        If FMID 				        If Abs(DX) < XACC Or FMID = 0 Then Exit Function
				    Next J
				    Print "too many bisections"
				End Function