c# 字符串排序 （面试题）

将一些字符串，如： "bc", "ad", "ac", "hello", "xman", "little", "during","day"

排序的结果：“ad”，"ac"，“bc”，“during”，“day”，“hello”，“little”，“xman”

采用框架自带的排序函数来调用自定义的Compare方法实现，代码段如下所示：

class Program
    {
        static void Main(string[] args)
        {
            string[] strArr = new string[] { "bc", "ad", "ac", "hello", "xman", "little", "during", "day"};
            List<string> strs = new List<string>();
            list.AddRange(strArr);

            /*
             * Sort string by asc
             * result : “ad”，"ac"，“bc”，“during”，“day”，“hello”，“little”，“xman”
             */
            list.Sort(new CompStr());
            foreach (string str in strs)
            {
                Console.WriteLine(str);
            }

            Console.WriteLine("------------");

            //Sort string by desc
            list.Sort(new CompStrDesc());
            foreach (string str in strs)
            {
                Console.WriteLine(str);
            }
            Console.ReadLine();
        }
    }

    public class CompStr : IComparer<string>
    {
        #region IComparer<string> Members

        public int Compare(string x, string y)
        {
            if (x.Length > 0 && y.Length > 0)
            {
                if (x[0].CompareTo(y[0]) == 0)
                {
                    return -x.CompareTo(y);
                }
            }
            return x.CompareTo(y);
        }

        #endregion
    }

    public class CompStrDesc : IComparer<string>
    {

        #region IComparer<string> Members

        public int Compare(string x, string y)
        {
            if (x.Length > 0 && y.Length > 0)
            {
                if (x[0].CompareTo(y[0]) == 0)
                {
                    return x.CompareTo(y);
                }
            }
            return -x.CompareTo(y);
        }

        #endregion
    }