[程序清单]（程序编号BR028）

10CLEAR

12GRAPH

13INPUT“A=?”;A,”B=?”;B,”C=?”;C,”D=?”;D,”X=?”;X

15LINE–(0,450),9

16SN

17LINE(0,0)-(200,450),0,3,B

20FORU=1TOA

30LINE–((U*200/A),10),9

31LINE–((U*200/A),0),0,2

32LINE–((*200/A-200/A),-10),9PRINTU

35NEXTU

50FORU=BTOCSTEPD

60P=U/(C/450)

70LINE-(0,P),9

80LINE–(10,P),0,2

90LPRINTU

100NEXTU

110LINE–(0,0),9

120FORI=200/ATO200STEP200/A

130INPUTM

140N=M/(C/450),:E=E+M

150S=S+N

160LINE-((I-200/A),N)-((I-200/A)+(200/A),N),0,1

161T=M

162IFT>ZTHENLETZ=T

170NEXTI

174K=S/A=E/A

176LINE(0,K)-(200,K),2,3

177LINE(50,470),9:CSIZE2PRINTX

190LINE–(0,0),9

191TEXT

192LF2

195LPRINT“

“;”E=”;INTE

196LPRINT“

“;”Z=”;INTZ

197LPRINT“

“;”L=”;INTL

200END