// Sample for String.Intern(String)

using System;

using System.Text;

​

public class Sample {

    public static void Main() {

    String s1 = "MyTest";//interned

    String s2 = new StringBuilder().Append("My").Append("Test").ToString(); //interned

        String str=new String('h',3);//not interned

        String str1=new StringBuilder().Append("My").Append("name").ToString(); //not interned

           String s11 = "String" + s1;//not interned

      String s12 = "String" + s1; //not interned,so s11 not ref equals to s12

    String singles="m";

        String bunny=new String('y',12);//not interned

        Console.WriteLine(String.IsNullOrEmpty(String.IsInterned(str))?"no":"yes");//no

        Console.WriteLine(String.IsNullOrEmpty(String.IsInterned(str1))?"no":"yes");//no

        Console.WriteLine(String.IsNullOrEmpty(String.IsInterned(singles))?"no":"yes");//yes

        Console.WriteLine(String.IsNullOrEmpty(String.IsInterned(bunny))?"no":"yes");//no

        String letter=new String('z',3);

        Console.WriteLine(String.IsNullOrEmpty(String.IsInterned(letter))?"no":"yes");//no

    String s3 = String.Intern(s2); //interned

    Console.WriteLine("s1 == '{0}'", s1);

    Console.WriteLine("s2 == '{0}'", s2);

    Console.WriteLine("s3 == '{0}'", s3);

        Console.WriteLine(String.IsInterned(s1));//yes

        Console.WriteLine(String.IsInterned(s2));//yes

        Console.WriteLine(String.IsInterned(s3));//yes

    Console.WriteLine("Is s2 the same reference as s1?: {0}", (Object)s2==(Object)s1); //false

    Console.WriteLine("Is s3 the same reference as s1?: {0}", (Object)s3==(Object)s1);//true

         bool interned = String.IsInterned(letter) != null;

         if (interned)

            Console.WriteLine(" is in the string intern pool."

                              );

         else

            Console.WriteLine(" is not in the string intern pool."

                              );        

    }

}