do print "1 encrypt" print "2 decrypt" input ": ";a if a = 1 then input "message to encrypt: ";b$ input "number seed for encrypting: ";c for d=0 to len(b$)-1 e$=mid$(b$,d+1,1) trace e$ g = asc(e$) f$ = f$ + chr$(g+c) next d print b$ print f$ f$ = "" end if if a = 2 then input "message to decrypt: ";b$ input "number seed for decrypting: ";c for d=0 to len(b$)-1 e$=mid$(b$,d+1,1) trace e$ g = asc(e$) f$ = f$ + chr$(g-c) next d print b$ print f$ f$ = "" end if loop