object o = null;
object p = null;
object q = new Object();

Console.WriteLine(Object.ReferenceEquals(o, p));
p = q;
Console.WriteLine(Object.ReferenceEquals(p, q));
Console.WriteLine(Object.ReferenceEquals(o, p));

int int1 = 3;
Console.WriteLine(Object.ReferenceEquals(int1, int1));
Console.WriteLine(int1.GetType().IsValueType);

String s1 = "String1";
String s2 = "String1";
Console.WriteLine("s1 = s2: {0}", Object.ReferenceEquals(s1, s2));
Console.WriteLine("{0} interned: {1}", s1, 
                  String.IsNullOrEmpty(String.IsInterned(s1)) ? "No" : "Yes");

String suffix = "A";
String s3 = "String" + suffix;
String s4 = "String" + suffix;
Console.WriteLine("s3 = s4: {0}", Object.ReferenceEquals(s3, s4));
Console.WriteLine("{0} interned: {1}", s3, 
                  String.IsNullOrEmpty(String.IsInterned(s3)) ? "No" : "Yes");