1 REM PROGRAM 'Bank Manager'
    2 REM from the book '2^5 Mathematical Programs in Basic'
    3 REM by Jakub Tatarkiewicz & Andrzej Witkowski
    4 REM English version by Piotr Pagowski
    5 MODE3:VDU 19,7,6;0;
    9 PRINT:PRINT:PRINT:PRINT"           H E L L O !          B A N K  M A N A G E R":PRINT:PRINT:PRINT       
   10 PRINT"Searched value,                code"
   20 PRINT"Time for saving or paying back  1"
   30 PRINT"Interest rate                   2" 
   40 PRINT"Final amount                    3"
   50 PRINT"Investment or loan              4"
   60 PRINT"Instalment/Dividends rate       5"    
   70 PRINT
   80 INPUT"Give a problem's code, please",K
   90 IF K=1 THEN GOTO 120
  100 INPUT"Time of operation (years)",N
  110 IF K=2 THEN GOTO 150
  120 INPUT"Interest rates(%) per year",I
  130 I=I/100
  140 IF K=3 THEN GOTO 180
  150 INPUT"Final amount-Is it to be paid(Yes=1,No=0)",T
  160 INPUT"Give amount, please",F
  170 IF T=1 THEN F=-F
  180 IF K=4 THEN GOTO 220
  190 INPUT"Start amount-Is it to be be paid in(Yes=1,No=0)",T  
  200 INPUT"Give amount, please",P
  210 IF T=1 THEN P=-P
  220 INPUT"How many times per year are interests added to the savings",D
  230 R=D
  240 IF K=5 THEN GOTO 300
  250 X=0
  260 INPUT"Instalments/Dividends-Do you pay in(Yes=1,No=0)",T   
  270 INPUT"Give amount, please",S
  280 IF T=1 THEN S=-S
  290 IF S=0 THEN GOTO 320
  300 INPUT"How many instalments per year",R  
  310 INPUT"Type of payment (back=1, ahead=0)",X
  320 IF K=2 THEN GOTO 610
  330 I1=(1+I/D)^(D/R)-1
  340 IF K=1 THEN GOTO 410
  350 IF K=3 THEN GOTO 790   
  360 IF K=4 THEN GOTO 1000    
  370 IF K=5 THEN GOTO 1100    
  380 PRINT"Wrong choice of the code"
  390 GOTO 10
  400 REM Time of saving or paying back
  410 C=S*(1+X*I1)/I1
  420 N=LOG((C-F)/(C+P))/LOG(1+I1)
  430 N=INT(N*1E2)*1E-2
  440 IF F<0 THEN GOTO 470
  450 PRINT"Final amount to be taken";F  
  460 GOTO 480
  470 PRINT"Final amount to be paid ";-F 
  480 PRINT"will be reached after ";N;" periods"
  490 PRINT"it means after";INT(10*N/R)/10;" years"
  500 GOTO 10000
  600 REM Interest rates
  610 IF S<>0 THEN GOTO 640
  620 I=((ABS(F/P))^(1/(D*N))-1)*D
  630 GOTO 750
  640 I=ABS(S)/(ABS(P)+ABS(F))
  650 I=I+(ABS(P)+ABS(F))/ABS(S)/(N^3*R^3)
  660 A=(1+I)^(N*R)-1
  670 C=S*(1+I*X)/I
  680 F1=A*(P+C)+P+F
  690 F2=N*R*(A+1)*(P+C)/(1+I)-A*C/I
  700 I1=I-F1/F2
  710 IF (I1-I)/I1<1E-6 THEN GOTO 740
  720 I=I1
  730 GOTO 650
  740 I=((I1+1)^(R/D)-1)*D
  750 I=INT(I*1E5)*1E-3
  760 PRINT"Interest rate per year"
  770 PRINT"is ";I;"%"  
  780 GOTO 10000
  790 REM Final amount
  800 C=S*(1+X*I1)/I1
  810 A=(1+I1)^(N*R)-1
  820 F=-(P+A*(P+C))
  830 F=INT(1E3*F)*1E-3
  840 PRINT"After ";N;" years the final amount"
  860 IF F<0 THEN GOTO 890
  870 PRINT"to be taken will be ";F  
  880 GOTO 10000
  890 PRINT"to be paid will be ";-F 
  900 GOTO 10000
 1000 REM Loan
 1010 C=S*(1+X*I1)/I1
 1020 A=(1+I1)^(N*R)-1
 1030 P=-(F+A*C)/(A+1)
 1040 P=INT(1E3*P)*1E-3
 1050 IF P<0 THEN 1080
 1060 PRINT"The borrowed amount ";P    
 1070 GOTO 10000
 1080 PRINT"The paid in amount ";-P   
 1090 GOTO 10000
 1100 REM Instalment rate
 1110 B=(1+I1*X)/I1
 1120 A=(1+I1)^(N*R)-1
 1130 S=-(F+P*(A+1))/(A*B)
 1140 S=INT(1E3*S)*1E-3
 1150 IF S<0 THEN GOTO 1180
 1160 PRINT"The dividends we will get: ";S   
 1170 GOTO 10000
 1180 PRINT"The instalments we have to pay ";-S  
10000 END