Data commit

Task/Commatizing-numbers/C-sharp/commatizing-numbers.cs

@@ -0,0 +1,48 @@
+static string[] inputs = {
+	"pi=3.14159265358979323846264338327950288419716939937510582097494459231",
+	"The author has two Z$100000000000000 Zimbabwe notes (100 trillion).",
+	"\"-in Aus$+1411.8millions\"",
+	"===US$0017440 millions=== (in 2000 dollars)"
+};
+
+void Main()
+{
+	inputs.Select(s => Commatize(s, 0, 3, ","))
+              .ToList()
+              .ForEach(Console.WriteLine);
+}
+
+string Commatize(string text, int startPosition, int interval, string separator)
+{
+	var matches = Regex.Matches(text.Substring(startPosition), "[0-9]*");
+	var x = matches.Cast<Match>().Select(match => Commatize(match, interval, separator, text)).ToList();
+	return string.Join("", x);
+}
+
+
+string Commatize(Match match, int interval, string separator, string original)
+{
+	if (match.Length <= interval)
+		return original.Substring(match.Index,
+                match.Index == original.Length ? 0 : Math.Max(match.Length, 1));
+	
+	return string.Join(separator, match.Value.Split(interval));
+}
+
+public static class Extension
+{
+	public static string[] Split(this string source, int interval)
+	{
+		return SplitImpl(source, interval).ToArray();
+	}
+	
+	static IEnumerable<string>SplitImpl(string source, int interval)
+	{
+		for	(int i = 1; i < source.Length; i++)
+		{
+			if (i % interval != 0) continue;
+			
+			yield return source.Substring(i - interval, interval);
+		}
+	}
+}