Microsoft .NET Interview Questions and Answers

Question: Write some code using interfaces, virtual methods, and an abstract class.

Answer: using System; public interface Iexample1 { int MyMethod1(); } public interface Iexample2 { int MyMethod2(); } public abstract class ABSExample : Iexample1, Iexample2 { public ABSExample() { System.Console.WriteLine("ABSExample constructor"); } public int MyMethod1() { return 1; } public int MyMethod2() { return 2; } public abstract void MyABSMethod(); } public class VIRTExample : ABSExample { public VIRTExample() { System.Console.WriteLine("VIRTExample constructor"); } public override void MyABSMethod() { System.Console.WriteLine("Abstract method made concrete"); } public virtual void VIRTMethod1() { System.Console.WriteLine("VIRTMethod1 has NOT been overridden"); } public virtual void VIRTMethod2() { System.Console.WriteLine("VIRTMethod2 has NOT been overridden"); } } public class FinalClass : VIRTExample { public override void VIRTMethod2() { System.Console.WriteLine("VIRTMethod2 has been overridden"); } }