hashtable definition with example in C#.Net

Hash table will useful for optimization of look ups. It is old dotnet frame work class, which is slower than the dictionary type collection.

For example:

using System;
using System.Collections;

class Example
{
    static void Main()
    {
 Hashtable objHash= new Hashtable();
 objHash[7] = "India";
 objHash[8] = "US";
 objHash[9] = "London";

 foreach (DictionaryEntry value in objHash)
 {
     Console.WriteLine("{0}, {1}", value.Key, value.Value);
 }
    }
} 

Output:
9,London
8, US
7, India