June 2018 Update

Task/Caesar-cipher/Ring/caesar-cipher.ring

@@ -0,0 +1,60 @@
+# Project : Caesar cipher
+# Date    : 2017/11/11
+# Author : Gal Zsolt (~ CalmoSoft ~)
+# Email   : <calmosoft@gmail.com>
+
+cipher = "pack my box with five dozen liquor jugs"
+abc = "abcdefghijklmnopqrstuvwxyz"
+see "text is to be encrypted:" + nl
+see cipher+ nl + nl
+str = ""
+key = random(24) + 1
+see "key = " + key + nl + nl
+see "encrypted:" + nl
+caesarencode(cipher, key)
+see str + nl + nl
+cipher = str
+see "decrypted again:" + nl
+caesardecode(cipher, key)
+see str + nl
+
+func caesarencode(cipher, key)
+       str = ""
+       for n = 1 to len(cipher)
+            if cipher[n] != " "
+               pos = substr(abc, cipher[n])
+               if pos + key < len(abc)
+                  str = str + abc[pos + key]
+               else
+                  if (pos+key)-len(abc) != 0
+                     str = str + abc[(pos+key)%len(abc)]
+                  else
+                      str = str +abc[key+pos]
+                  ok
+                    ok
+               else
+                  str = str + " "
+               ok
+       next
+     return str
+
+func caesardecode(cipher, key)
+       str = ""
+       for n= 1 to len(cipher)
+            if cipher[n] != " "
+               pos = substr(abc, cipher[n])
+               if (pos - key) > 0 and pos != key
+                   str = str + abc[pos - key]
+                   loop
+               else
+                   if pos = key
+                      str = str + char(122)
+                   else
+                     str = str + abc[len(abc)-(key-pos)]
+                   ok
+               ok
+            else
+               str = str + " "
+            ok
+       next
+       return str