YAPC::EU 2018 Glasgow Update!

Task/Caesar-cipher/ZX-Spectrum-Basic/caesar-cipher-2.zx

@@ -0,0 +1,30 @@
+10 LET t$="Wonderful ZX Spectrum."
+20 LET c$="a":REM more characters, more difficult for decript
+30 LET CIFRA=1: LET DESCIFRA=-1
+40 PRINT t$''
+50 LET modo=CIFRA: GO SUB 1000
+60 PRINT r$''
+70 LET t$=r$: LET modo=DESCIFRA: GO SUB 1000
+80 PRINT r$''
+90 STOP
+1000 REM Criptex
+1010 LET p$="abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890 .,;:()-"
+1020 LET longPatron=LEN p$
+1030 LET longTexto=LEN t$
+1040 LET longClave=LEN c$
+1045 LET k=0: LET r$=""
+1050 FOR i=1 TO longTexto
+1060 LET k=k+1: IF k>longClave THEN LET k=1
+1070 LET x$=t$(i)
+1080 FOR j=1 TO longPatron
+1090 IF x$=p$(j) THEN LET delta=j: GO TO 1110
+1100 NEXT j
+1110 LET x$=c$(k)
+1120 FOR j=1 TO longPatron
+1130 IF x$=p$(j) THEN LET delta=delta+modo*j: GO TO 1150
+1140 NEXT j
+1150 IF delta>longPatron THEN LET delta=delta-longPatron: GO TO 1170
+1160 IF delta<1 THEN LET delta=longPatron+delta
+1170 LET r$=r$+p$(delta)
+1180 NEXT i
+1190 RETURN