Data commit

Task/Caesar-cipher/PureBasic/caesar-cipher-1.basic

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+Procedure.s CC_encrypt(plainText.s, key, reverse = 0)
+  ;if reverse <> 0 then reverse the encryption (decrypt)
+  If reverse: reverse = 26: key = 26 - key: EndIf
+
+  Static alphabet$ = "ABCEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz"
+
+  Protected result.s, i, length = Len(plainText), letter.s, legal
+  If key < 1 Or key > 25: ProcedureReturn: EndIf  ;keep key in range
+
+  For i = 1 To length
+    letter = Mid(plainText, i, 1)
+    legal = FindString(alphabet$, letter, 1 + reverse)
+    If legal
+      result + Mid(alphabet$, legal + key, 1)
+    Else
+      result + letter
+    EndIf
+  Next
+  ProcedureReturn result
+EndProcedure
+
+Procedure.s CC_decrypt(cypherText.s, key)
+  ProcedureReturn CC_encrypt(cypherText, key, 1)
+EndProcedure
+
+If OpenConsole()
+  Define key, plainText.s, encryptedText.s, decryptedText.s
+
+  key = Random(24) + 1 ;get a random key in the range 1 -> 25
+
+  plainText = "The quick brown fox jumped over the lazy dogs.": PrintN(RSet("Plain text = ", 17) + #DQUOTE$ + plainText + #DQUOTE$)
+  encryptedText = CC_encrypt(plainText, key): PrintN(RSet("Encrypted text = ", 17) + #DQUOTE$ + encryptedText + #DQUOTE$)
+  decryptedText = CC_decrypt(encryptedText, key): PrintN(RSet("Decrypted text = ", 17) + #DQUOTE$ + decryptedText + #DQUOTE$)
+
+  Print(#CRLF$ + #CRLF$ + "Press ENTER to exit"): Input()
+  CloseConsole()
+EndIf