C# 索引器

string s = "hello"; 
Console.WriteLine (s[0]); // "h" 
Console.WriteLine (s[3]); // "l" 

class MyWord { 
   string[] words = "this is a test".Split(); 
   
   public string this [int wordNum] // indexer 
   { 
       get { 
           return words [wordNum]; 
       } 
       set { 
           words [wordNum] = value; 
       } 
   } 
} 

MyWord s = new MyWord(); 
Console.WriteLine (s[3]);
s[3] = "CSS"; 
Console.WriteLine (s[3]); // CSS

public string this [int arg1, string arg2] {
    get { ... } set { ... } 
}