76 lines
1.5 KiB
Plaintext
76 lines
1.5 KiB
Plaintext
import system'routines;
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import system'math;
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import extensions;
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import extensions'text;
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const string Letters = "abcdefghijklmnopqrstuvwxyz";
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const string BigLetters = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
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const string TestText = "Pack my box with five dozen liquor jugs.";
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const int Key = 12;
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class Encrypting : Enumerator
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{
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int theKey;
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Enumerator theEnumerator;
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constructor(int key, string text)
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{
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theKey := key;
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theEnumerator := text.enumerator();
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}
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bool next() => theEnumerator;
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reset() => theEnumerator;
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enumerable() => theEnumerator;
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get()
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{
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var ch := theEnumerator.get();
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var index := Letters.indexOf(0, ch);
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if (-1 < index)
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{
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^ Letters[(theKey+index).mod:26]
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}
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else
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{
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index := BigLetters.indexOf(0, ch);
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if (-1 < index)
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{
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^ BigLetters[(theKey+index).mod:26]
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}
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else
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{
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^ ch
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}
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}
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}
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}
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extension encryptOp
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{
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encrypt(key)
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= new Encrypting(key, self).summarize(new StringWriter());
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decrypt(key)
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= new Encrypting(26 - key, self).summarize(new StringWriter());
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}
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public program()
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{
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console.printLine("Original text :",TestText);
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var encryptedText := TestText.encrypt:Key;
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console.printLine("Encrypted text:",encryptedText);
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var decryptedText := encryptedText.decrypt:Key;
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console.printLine("Decrypted text:",decryptedText);
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console.readChar()
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}
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