C#索引器Week例子

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using System;namespace CSharpBook.Chapter07{    class DayCollection    {   // 星期（字符串）数组        string[] days = { "Sun", "Mon", "Tues", "Wed", "Thurs", "Fri", "Sat" };        public int this[string index]        {            get {                for (int i = 0; i < days.Length; i++)                {                    if (days[i] == index)                    {                        return i;                    }                }                return -1;            }         }    }    class Program    {        static void Main(string[] args)        {            DayCollection week = new DayCollection();            Console.WriteLine("{0}:{1}", "Friday", week["Fri"]);            Console.WriteLine("{0}:{1}", "Unknown", week["Unknown"]);            Console.ReadLine();        }    }} 

输出结果：

friday:5

unknown:-1