dictionary in C#

C# support dictionary in generic collections.
```
using System; 
using System.Collections.Generic;   
  
class C { 
    static public void Main () { 
        Dictionary<char, int> d =  new Dictionary<char, int>();  
        d.Add('a', 1); 
        d.Add('b', 2); 
        d.Add('c', 3); 
        d['a'] = 0;
        d.Remove('b');
        foreach(KeyValuePair<char, int> i in d) { 
            Console.WriteLine("{0}", i.Value); 
        } 
        d.Clear();
    } 
} 
```