Hopefully, I'm not too off topic here but bare with me a bit.

I'm trying to convert the Bifid decryption tools in Caxton Foster's book<I><s>

*</s> Cryptanalysis for microcomputers. <e>*</e></I> I have typed the programs as they are presented (line numbers included) in his book in Chapter 13 but, try as I may, I cannot get it to run without a bad function call (error #5) for the line Print chr$(t+64);"reverse off"; in line 770.

Here are my few ideas why it is not working:

- There is something specific to PET BASIC I'm unfamiliar with and have not accounted for,
- The program itself is faulty,
- The program works only in interpreter mode but not when compiled (haven't tested that yet),
- There is a conflict between PETSCII and ASCII,
- There are too may GOTOs, GOSUBs and labels,
- Some variable names are too close to each other which confused the compiler (e.g. T & T%() and lastly (taa-daa),
- I have made a monumental stoooopid that I can't find.

Again, thank you all for your help.

Code: Select all

```
1 DIM T%(1000), L1(26), L2(26), TA%(1000), TB%(1000), TC%(1000)
4 DIM TP%(50), R%(1000), C%(1000), B(11), LB(11)
5 DIM KS%(9, 9), RL%(26), CL%(26)
10 REM DETERMINE PERIOD
20 REM OPEN FILES, READ AND PURGE
25 GOSUB 90000: REM Set UP And OPEN FILES
30 GOSUB 10000: REM READ DATA FROM FILE
40 GOSUB 10200: REM REMOVE UNWANTED CHARACTERS & SPACES
41 PRINT "DO YOU KNOW THE PERIOD? TYPE Y OR N."
42 A$ = "": A$ = INKEY$: IF A$ = "" GOTO 42
43 IF UCASE$(A$) = "Y" GOTO 300
45 PRINT "PERIOD IC"
50 FOR P = 3 TO 20
55 FOR Q = 1 TO 26: L1(Q) = 0: NEXT Q
60 HP = INT(P / 2)
70 OD = P - 2 * HP
75 S = 0
80 TA% = 0: K = 0
90 FOR B = 0 TO J - P STEP P
100 FOR X = 1 TO HP + OD
110 F = T%(B + X)
120 G = T%(B + X + HP)
125 S = S + 1
130 GOSUB 1000
140 NEXT X
150 FOR X = 1 TO HP
160 L1(T%(X + B)) = L1(T%(X + B)) + 1
170 L2(T%(B + P + 1 - X)) = L2(T%(B + P + 1 - X)) - 1
180 NEXT X
190 NEXT B
200 IC = 0
210 GOSUB 2000
220 GOSUB 3000
230 PRINT P; INT((IC * 625) + .5); INT(CS + .5): REM MODIFIED TO SHOW INTEGER VALUES ONLY
240 NEXT P
250 REM PLACE THE TIP (SUSPECTED WORD OR PHRASE ENCIPHERED WITHIN THE MESSAGE)
300 INPUT "WHAT IS THE PERIOD? "; P
320 HP = INT(P / 2)
330 OD = P - 2 * HP
340 INPUT "ENTER THE TIP -- NO BLANKS "; A$
355 TL = LEN(A$)
360 FOR I = 1 TO TL
370 TP%(I) = ASC(MID$(A$, I, 1)) - 64: REM INDEX OMITTED IN ORIGINAL LISTING
380 NEXT I
390 REM MAKE VECTORS OF ROW AND COLUMN ELEMENTS: AR = 1, AC = 101
400 K = 1
401 REM SEE ALSO: ALTERNATE CODE ON P. 243
410 FOR B = 0 TO J - P STEP P
415 C%(K) = T%(B + 1)
420 FOR X = 1 TO HP + OD
430 R%(K) = T%(B + X)
440 R%(K + 1) = T%(B + X) - 100
445 C%(K + 1 - OD) = T%(B + X + HP) + 100
450 C%(K + 2 - OD) = T%(B + X + HP + 1)
460 K = K + 2
470 NEXT X
480 K = K - OD
490 NEXT B
495 B(11) = 10000: FOR XX = 1 TO 10: B(XX) = 0: NEXT XX
500 IF OD = 0 GOTO 610
510 REM FIND ODD PERIOD NATURALS
520 FOR I = 0 TO B - TL
530 C = 0
540 FOR K = 1 TO TL
550 IF R%(I + K) = TP%(K) THEN C = C + 1
560 IF C%(I + K) = TP%(K) + 100 THEN C = C + 1
570 NEXT K
580 GOSUB 4000
590 NEXT I
600 GOTO 700
610 REM DO IDENTICALS FOR EVEN PERIOD
620 FOR I = 0 TO B - TL
630 C = 0
640 FOR K = 1 TO TL
650 IF (TP%(K) = R%(I + K)) AND (TP%(K + 1) = C%(I + K)) THEN C = C + 2
670 NEXT K
680 GOSUB 4000
690 NEXT I
700 PRINT: PRINT "PT=" ': REM CHECK THIS ORIGINALLY 700 PRINT: PRINT "PT='
710 FOR I = 1 TO TL
720 PRINT CHR$(TP%(I) + 64);
730 NEXT I
735 PRINT
740 FOR I = 10 TO 1 STEP -1
745 IF B(I) = 0 GOTO 830
750 PRINT LB(I),
760 FOR X = 1 TO TL
765 T = R%(LB(I) + X): IF T > 100 THEN T = T - 100: PRINT "reverse";
770 PRINT CHR$(T + 64); "reverse off";
780 NEXT X
790 PRINT: PRINT ,
800 FOR X = 1 TO TL
805 T = C%(LB(I) + X): IF T > 100 THEN T = T - 100: PRINT "reverse";
810 PRINT CHR$(T + 64); "reverse off";
820 NEXT X
825 PRINT
830 NEXT I
833 CLOSE #2
835 A$ = "": A$ = INKEY$: IF A$ = "" THEN GOTO 835
840 STOP
1000 FOR Y = 1 TO K
1010 IF (F = TA%(Y)) AND (G = TB%(Y)) THEN TC%(Y) = TC%(Y) + 1: RETURN
1020 NEXT Y
1030 K = K + 1
1040 TA%(K) = F
1050 TB%(K) = G
1060 TC%(K) = I
1070 RETURN
2000 FOR Y = 1 TO K
2010 IC = IC + TC%(Y) * (TC%(Y) - 1)
2020 NEXT Y
2030 IC = IC / (S * (S - 1))
2040 RETURN
3000 CS = 0
3010 FOR Z = 1 TO 26
3015 IF L1(Z) + L2(Z) = 0 GOTO 3030
3020 CS = CS + (L1(Z) - L2(Z)) ^ 2 / (L1(Z) + L2(Z))
3030 NEXT Z
3040 RETURN
4000 IF C < B(1) THEN RETURN
4010 FOR XX = 2 TO 11
4020 IF C < B(XX) THEN B(XX - 1) = C: LB(XX - 1) = I: RETURN
4030 B(XX - 1) = B(XX)
4040 LB(XX - 1) = LB(XX)
4050 NEXT XX
4060 RETURN
10000 REM Read in the text
10010 J = 0
10020 F = 0
10030 CLS: PRINT
10040 PRINT "ENTERING TEXT FROM FILE"
10045 PRINT: PRINT
10050 LINE INPUT #1, A$
10055 PRINT A$
10060 FOR I = 1 TO LEN(A$)
10070 X = ASC(MID$(A$, I, 1)) - 64
10080 IF X = -17 THEN F = 1
10090 J = J + 1
10100 T%(J) = X
10110 NEXT I
10120 IF F = 0 GOTO 10050
10121 SLEEP 5: PRINT: PRINT
10130 J = J - 1
10135 CLOSE #1
10140 RETURN
10200 REM SQUEESE OUT THE BLANKS
10210 I = 0
10220 FOR K = 1 TO J
10230 IF T%(K) < 1 OR T%(K) > 26 GOTO 10260
10240 I = I + 1
10250 T%(I) = T%(K)
10260 NEXT K
10270 J = I
10280 RETURN
90000 REM OPEN INPUT AND OUTPUT FILE
90005 SCREEN _NEWIMAGE(800, 600, 256): REM SET SCREEN PROPERTIES
90010 CLS
90020 INPUT "WHAT IS THE NAME OF THE INPUT FILE > "; A$
90030 OPEN A$ FOR INPUT AS #1
90040 PRINT: PRINT
90050 INPUT "WHAT IS THE NAME OF THE OUTPUT FILE > "; A$
90060 OPEN A$ FOR OUTPUT AS #2
90070 RETURN
```