用VB实现数值积分的算法集。包括梯形求积法

				Sub QTRAP(A, B, S)
				    EPS = 0.000001
				    JMAX = 20
				    OLDS = -1E+30
				    For J = 1 To JMAX
				        Call TRAPZD(A, B, S, J)
				        If Abs(S - OLDS) < EPS * Abs(OLDS) Then Exit Sub
				        OLDS = S
				    Next J
				    Print "Too many steps."
				End Sub