Caesar cipher: Difference between revisions
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Cyril Nocton (talk | contribs) |
Cyril Nocton (talk | contribs) |
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=={{header|Common Lisp}}== |
=={{header|Common Lisp}}== |
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====W/ decipher function==== |
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<lang lisp>(defun encipher-char (ch key) |
<lang lisp>(defun encipher-char (ch key) |
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(let* ((c (char-code ch)) (la (char-code #\a)) (ua (char-code #\A)) |
(let* ((c (char-code ch)) (la (char-code #\a)) (ua (char-code #\A)) |
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"Qeb nrfzh yoltk clu grjmp lsbo qeb ixwv ald" |
"Qeb nrfzh yoltk clu grjmp lsbo qeb ixwv ald" |
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> (caesar-decipher "Qeb nrfzh yoltk clu grjmp lsbo qeb ixwv ald" 23) |
> (caesar-decipher "Qeb nrfzh yoltk clu grjmp lsbo qeb ixwv ald" 23) |
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"The quick brown fox jumps over the lazy dog" |
"The quick brown fox jumps over the lazy dog"</pre> |
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====W/o decipher function==== |
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</pre> |
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1. Note |
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<pre>if rot(text shift) = cyphertext then rot(cyphertext -shift) = text</pre> |
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2. Program |
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Text manipulation is a real pain in the arse. Requiescat in pace. |
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<lang lisp>(defconstant +rot+ "AaBbCcDdEeFfGgHhIiJjKkLlMmNnOoPpQqRrSsTtUuVvWwXxYyZz") |
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(defun rot (text shift) |
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;; ask cyril:nocton@gmail.com |
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(map 'string |
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#'(lambda (x) |
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(if (find x +rot+) |
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(char +rot+ (mod (+ (position x +rot+) (* 2 shift)) 52)) |
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x)) |
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text))</lang> |
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3. Execution |
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See 1. |
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{{out}} |
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<pre>(rot "Ave Caesar morituri te salutant" 13) |
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Nir Pnrfne zbevghev gr fnyhgnag |
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(rot "Nir Pnrfne zbevghev gr fnyhgnag" -13) |
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Ave Caesar morituri te salutant</pre> |
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=={{header|Delphi}}== |
=={{header|Delphi}}== |
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