September 2017 Update

Task/Caesar-cipher/VBScript/caesar-cipher.vb

@@ -0,0 +1,35 @@
+	str = "IT WAS THE BEST OF TIMES, IT WAS THE WORST OF TIMES."
+
+	Wscript.Echo str
+	Wscript.Echo Rotate(str,5)
+	Wscript.Echo Rotate(Rotate(str,5),-5)
+
+	'Rotate (Caesar encrypt/decrypt) test <numpos> positions.
+	'  numpos < 0 - rotate left
+	'  numpos > 0 - rotate right
+	'Left rotation is converted to equivalent right rotation
+
+	Function Rotate (text, numpos)
+
+		dim dic: set dic = CreateObject("Scripting.Dictionary")
+		dim ltr: ltr = Split("A B C D E F G H I J K L M N O P Q R S T U V W X Y Z")
+		dim rot: rot = (26 + numpos Mod 26) Mod 26 'convert all to right rotation
+		dim ch
+		dim i
+
+		for i = 0 to ubound(ltr)
+			dic(ltr(i)) = ltr((rot+i) Mod 26)
+		next
+
+		Rotate = ""
+
+		for i = 1 to Len(text)
+			ch = Mid(text,i,1)
+			if dic.Exists(ch) Then
+				Rotate = Rotate & dic(ch)
+			else
+				Rotate = Rotate & ch
+			end if
+		next
+
+	End Function