using static System.Console;

using System.Text;

​

public static class Program {

    public static void Main() {

        WriteLine("CamelCase".SplitCamelCase());

        WriteLine("Camel-Case".SplitCamelCase());

        WriteLine("Camel---Case".SplitCamelCase());

        WriteLine("Camel.Case".SplitCamelCase());

        WriteLine("Ca".SplitCamelCase());

        WriteLine("aC".SplitCamelCase());

        WriteLine("CC".SplitCamelCase());

        WriteLine("C".SplitCamelCase());

        WriteLine("CamelCaseC".SplitCamelCase());

        WriteLine("".SplitCamelCase());

        WriteLine("pascalCase".SplitCamelCase());

        WriteLine("CamelCase".SplitCamelCase('-', ""));

        WriteLine("Camel-Case".SplitCamelCase('-', ""));

        WriteLine("Camel---Case".SplitCamelCase('-', ""));

        WriteLine("Camel.Case".SplitCamelCase('-', ""));

        WriteLine("Ca".SplitCamelCase('-', ""));

        WriteLine("aC".SplitCamelCase('-', ""));

        WriteLine("CC".SplitCamelCase('-', ""));

        WriteLine("C".SplitCamelCase('-', ""));

        WriteLine("CamelCaseC".SplitCamelCase('-', ""));

        WriteLine("".SplitCamelCase('-', ""));

        WriteLine("pascalCase".SplitCamelCase('-', ""));

    }

    public static string SplitCamelCase(this string text, char separator = '-', string separators = "-=_+!@#$%&*()'^~[]{}/?;:.,<>|\\\"") {

        if (string.IsNullOrEmpty(text) || text.Length < 2) return text;

        var sb = new StringBuilder(text.Length + text.Length / 3);

        for (var i = 0; i < text.Length; i++) {

            if (char.IsUpper(text[i]) && i > 0 && !separators.Contains(text[i - 1].ToString())) sb.Append(separator);

            sb.Append(text[i]);

        }

        return sb.ToString();

    }

}