10 REM ROT13 CODE
15 LET CODE$ = "AaBbCcDdEeFfGgHhIiJjKkLlMmNnOoPpQqRrSsTtUuVvWwXxYyZz"
20 INPUT A$
30 FOR I = 1 TO LEN(A$)
40 LET B$ = MID$(A$,I, 1)
50 LET TAR = INSTR(CODE$, B$, 1)
60 IF TAR = 0 THEN 90
70 LET TAR = (TAR + 26) MOD 52
80 LET B$ = MID$(CODE$, TAR, 1)
90 PRINT B$;
100 NEXT I
110 PRINT ""
120 GOTO 20


