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Talk:Substitution cipher: Difference between revisions
→Task: substitute cipher in PowerBASIC
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== Old Things may be woken! ==
I daren't read the REXX cypher-text out loud. Old Things may be woken! --[[User:Tim-brown|Tim-brown]] ([[User talk:Tim-brown|talk]]) 07:07, 15 October 2015 (UTC)
:: Yes, it does sound like some strange incantation, like a record being played backward. -- [[User:Gerard Schildberger|Gerard Schildberger]] ([[User talk:Gerard Schildberger|talk]]) 15:06, 14 January 2020 (UTC)
== Task needs to specify some examples ==
This task should really specify some examples to be tried by each implementation. --[[User:Rdm|Rdm]] ([[User talk:Rdm|talk]]) 14:32, 15 October 2015 (UTC)
== Task: substitute cipher in PowerBASIC ==
=={{header|PowerBASIC}}==
<lang PowerBASIC>
'PBCC 6.03 version
' uses same alphabet and key as Ada language example
$string1 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
$string2 = "VsciBjedgrzyHalvXZKtUPumGfIwJxqOCFRApnDhQWobLkESYMTN"
%true = -1
%false = 0
FUNCTION PBMAIN() AS LONG
PROCESS1 "plain.txt", "encrypted.txt", %true
PROCESS1 "encrypted.txt", "decrypted.txt",%false
PRINT
PRINT "Press any key to quit"
WAITKEY$
END FUNCTION
SUB process1(inputFile AS STRING, outputFile AS STRING, encrypt AS INTEGER)
DIM i AS INTEGER
OPEN inputFile FOR INPUT AS #1
IF ERR > 0 THEN
PRINT "Unable to open input file"
WAITKEY$
END
END IF
DIM alpha AS STRING, key1 AS STRING
IF encrypt THEN
alpha = $string1 : key1 = $string2
ELSE
alpha = $string2 : key1 = $string1
END IF
OPEN outputFile FOR OUTPUT AS #2
DIM s AS STRING
DIM p AS INTEGER
DIM currentChar AS INTEGER
WHILE NOT EOF(1)
LINE INPUT #1, s
FOR i = 1 TO LEN(s)
currentChar = ASC(MID$(s, i, 1))
IF (currentChar >= 65 AND currentChar <= 90) OR (currentChar >= 97 AND currentChar <= 122) THEN
p = INSTR(alpha, MID$(s, i, 1))
MID$(s, i, 1) = MID$(key1, p, 1)
END IF
NEXT
PRINT #2, s
WEND
CLOSE #1 : CLOSE #2
END SUB
</lang>
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