introductory-examples/program-organization/2/ex.cs - Two namespaces and a nested namespace with classes.

Lecture 4 - slide 19 : 29 Program 3

// Several namespaces, including nested namespaces.
// In source file ex.cs

namespace N1 {
  public class C1{};
}


namespace N2 {
  internal class C2{};
  public class C3{};

  namespace N3 {
     public class C4{
       C2 v;
     }
  }
}