title: C# interface method declared in Base class need not be again implemented in Derived class
body: <p>It could be a silly question, but I am learning, and I was just curious what's happening, today I was playing with few oops concepts and learning it in VS. I was again puzzled to see that we don't have to implement multiple interfaces same method into a derived class where ACTUALLY we "inherit" the interface, but in base class. </p>
  
  <p>May I know how it works? My concern is, even though I do not "inherit" interface methods in base class, I use a method with same name. I also do not implement it in derived class. </p>
  
  <p>Can somebody help me understand what's happening and how and why?</p>
  
  <pre><code>Class A
  {
      public void Display()
      {
          Console.Writeline("I am from A");
      }
  }
  
  interface IA
  {
      void Display();
  }
  
  interface IB
  {
      void Display();
  }
  
  Class B : A, IA, IB
  {
  
  }
  
  Class Final
  {
      static void Main()
      {
          B b = new B();
          b.Display(); // displays class A Display method.
          Console.Readline();
      }
  }
  </code></pre>