用于开发税务票据管理的软件

				unit Unit2;
				
				interface
				procedure GAULEG(X1, X2:real;var X, W:array of real; N:integer);
				
				implementation
				procedure GAULEG(X1, X2:real;var X, W:array of real; N:integer);
				label 1;
				const
				    EPS = 0.3e-13;
				var
				    M,I,J:integer;
				    XM,XL,P1,P2,P3,PP,Z,Z1:real;
				begin
				    M:=Trunc((N + 1) / 2);
				    XM:=0.5 * (X2 + X1);
				    XL:=0.5 * (X2 - X1);
				    For I:=1 To M do
				    begin
				        Z:=Cos(3.141592654 * (I - 0.25) / (N + 0.5));
				1:      P1:=1;
				        P2:=0;
				        For J:=1 To N do
				        begin
				            P3:=P2;
				            P2:=P1;
				            P1:=((2 * J - 1) * Z * P2 - (J - 1) * P3) / J;
				        end;
				        PP:=N * (Z * P1 - P2) / (Z * Z - 1);
				        Z1:=Z;
				        Z:=Z1 - P1 / PP;
				        If Abs(Z - Z1) > EPS Then GoTo 1;
				        X[I]:=XM - XL * Z;
				        X[N + 1 - I]:=XM + XL * Z;
				        W[I]:=2 * XL / ((1 - Z * Z) * PP * PP);
				        W[N + 1 - I]:=W[I];
				    end;
				end;
				end.