public class Demo
{
 void show()
 {   
  Console.WriteLine("Welcome to Class Library Project");
 }
}

using Demo;//Implementing class library in our application
class MyProgram
{
 static void Main(String args[])
 {
  //creating object of class library class
  Demo d = new Demo();
  //using the show method of the class library
  d.show();
 }
}