Data commit

Task/Move-to-front-algorithm/VBScript/move-to-front-algorithm.vb

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+Function mtf_encode(s)
+	'create the array list and populate it with the initial symbol position
+	Set symbol_table = CreateObject("System.Collections.ArrayList")
+	For j = 97 To 122 'a to z in decimal.
+		symbol_table.Add Chr(j)
+	Next
+	output = ""
+	For i = 1 To Len(s)
+		char = Mid(s,i,1)
+		If i = Len(s) Then
+			output = output & symbol_table.IndexOf(char,0)
+			symbol_table.RemoveAt(symbol_table.LastIndexOf(char))
+			symbol_table.Insert 0,char
+		Else
+			output = output & symbol_table.IndexOf(char,0) & " "
+			symbol_table.RemoveAt(symbol_table.LastIndexOf(char))
+			symbol_table.Insert 0,char
+		End If
+	Next
+	mtf_encode = output
+End Function
+
+Function mtf_decode(s)
+	'break the function argument into an array
+	code = Split(s," ")
+	'create the array list and populate it with the initial symbol position
+	Set symbol_table = CreateObject("System.Collections.ArrayList")
+	For j = 97 To 122 'a to z in decimal.
+		symbol_table.Add Chr(j)
+	Next
+	output = ""
+	For i = 0 To UBound(code)
+		char = symbol_table(code(i))
+		output = output & char
+		If code(i) <> 0 Then
+			symbol_table.RemoveAt(symbol_table.LastIndexOf(char))
+			symbol_table.Insert 0,char
+		End If
+	Next
+	mtf_decode = output	
+End Function
+
+'Testing the functions
+wordlist = Array("broood","bananaaa","hiphophiphop")
+For Each word In wordlist
+	WScript.StdOut.Write word & " encodes as " & mtf_encode(word) & " and decodes as " &_
+		mtf_decode(mtf_encode(word)) & "."
+	WScript.StdOut.WriteBlankLines(1)
+Next