如何获得数组的所有子集？

 string[] source = new string[] { "dog", "cat", "mouse" }; for (int i = 0; i < Math.Pow(2, source.Length); i++) {     string[] combination = new string[source.Length];     for (int j = 0; j < source.Length; j++)     {         if ((i & (1 << (source.Length - j - 1))) != 0)         {  combination[j] = source[j];         }    }    Console.WriteLine("[{0}, {1}, {2}]", combination[0], combination[1], combination[2]);}