10 'Bisection Method
20 SCREEN 0,0,0:CLS
30 PRINT "Initial conditions : "
40 PRINT "Initial Gas Chamber Pressure (P3 = P2) = 15.3 Kg/cm2 a"
50 PRINT "Equiv. length L1(liq) = 125 ft; L2 (gas) =  48 ft"
60 PRINT "Dia. d1(liq) = 1.61 in. ; d2 (gas) = .5 in."
70 PRINT "Initial gas chamber volume : .15 m3"
80 'INPUT "Enter the Dia d1 (inches) :";D1
90 'INPUT "Enter the dia d2 (inches  :";D2
100 'INPUT "Enter the equvalent lenght L1 (ft) :";L1
110 'INPUT "Enter the equvalent lenght L2(ft)  :";L2
120 IF INKEY$="" THEN 120
130 D1=1.61:D2=.5:L1=125:L2=48
140 K1=(16.2/((6018)^2))+(4.54*(10^-8)*L1/(100*(D1^5)))
150 K2=(1/K1)^.5
160 K3=3.1863*(10^-6)*L2/(100*(D2^5))
170 K4=(1/K3)^.5
180 V=.15:R=8.910001E-02:TE=324:Z=1!:M=30:P2=15.3:C2=2.295
190 'T=1/3600
200 CLS:PRINT "Time             P3           Wl            Wg            P1           PD"
210     PRINT " (s)           (Kg/cm2 a)   (Kg/hr)       (Kg/hr)       (Kg/cm2 a)  (Kg/cm2)"
220 FOR T=0  TO 20/3600  STEP .1/3600
240 IF COUNT >20 THEN 241 ELSE 270
241 IF INKEY$="" THEN 241
250 COUNT=0:CLS:PRINT "Time             P3           Wl            Wg            P1           PD"
260     PRINT " (s)           (Kg/cm2 a)   (Kg/hr)       (Kg/hr)       (Kg/cm2 a)  (Kg/cm2)"
270 DEF FNA(P)=(K2*T/3000)*(5*P+1.8)*((P+.9)^(.5))-K4*(R*TE*Z/M)*T*((P2-P)^(.5))+V*P-C2
280 CTR=0
290 A=15.3:B=14
300 'LOCATE 10,15:PRINT "Enter the two guesses now"
310 'LOCATE 12,15:PRINT "Enter a :"
320 'LOCATE 14,15:PRINT "Enter b :"
330 'LOCATE 12,15:INPUT "Enter a :";A
340 'LOCATE 14,15:INPUT "Enter b :";B
350 FUNA=FNA(A):FUNB=FNA(B)
360 IF FUNA=0 THEN ROOT=A:GOTO 480
370 IF FUNB=0 THEN ROOT=B:GOTO 480
380 IF FUNA >0 AND FUNB>0 THEN 400 ELSE 390
390 IF FUNA<0 AND FUNB<0 THEN 400 ELSE 430
400 CLS:LOCATE 10,13:PRINT "The function must have different sign values at a and b"
410 LOCATE 20,25:PRINT "PRESS ANY KEY TO CONTINUE"
420 IF INKEY$="" THEN 420 ELSE 270
430 X1=(A+B)/2
440 CTR=CTR+1
450 FUNX1=FNA(X1)
460 IF FUNX1<.01 AND FUNX1>-.01 THEN 470 ELSE 580
470 ROOT=X1
480 'CLS:LOCATE 10,20:PRINT "The root of the equation is :";ROOT
490 WL=((ROOT+.9)^.5)*K2
500 WG=((P2-ROOT)^.5)*K4
510 P1=(WL^2)*16.2/(6018^2)
520 PD = P1-ROOT
530 PRINT ST,ROOT,WL,WG,P1;"   ";PD
531 ST=ST+.1:COUNT=COUNT+1
540 'LOCATE 13,20:PRINT "Number of iterations :";CTR
550 'LOCATE 20
560 'IF INKEY$="" THEN 560
570 NEXT 'END
580 IF FUNA >0 AND FUNX1>0 THEN A=X1
590 IF FUNA <0 AND FUNX1<0 THEN A=X1
600 IF FUNB >0 AND FUNX1>0 THEN B=X1
610 IF FUNB <0 AND FUNX1<0 THEN B=X1
620 FUNA=FNA(A):FUNB=FNA(B):GOTO 430