Listing 10-12 extracted from chapter The .NET 2 type system from a C#2 point of view

Listing 10-11<     > Listing 10-13

This listing can be compiled with the command line:
csc.exe /target:exe Example_10_12.cs
Errors: 0 Warnings: 0

class Program {
   public static void Main() {
      int i = 9;
      object o = i;    // i is 'boxed'.
      int j = (int) o;  // o is 'unboxed'.
   }
}