Constructors need to be overloaded depending on what extend of data/properties need to be initialized in order to set the object to a particular state. Below a good example using a Customer / Orders example. Note that Customer constructor is overloaded in 3 different ways based on what data need to be initialized. Here we…

Composition is a common object oriented concept that enables us to implement loose coupling as well as code-reuse. Lot of times we recommend our developers to use more composition and less inheritance due this very fact. Inheritance supports code-reuse, but makes application tightly coupled and creates long inheritance hierarchies that creates inter-dependencies. Inheritance implements a…

Like any other Object Oriented Programming language, C# does not allow parent constructor to be automatically inherited. It need to explicitly defined in the derived class. Below is an example to explain this – Below is the parent class – namespace ConstructorInh {     public class Fruit     {         private readonly string _color;         public Fruit(string color)         {             _color = color;             Console.WriteLine(“I am a Fruit with Color {0}”, _color);         }     } } Below is the…

C# Generics are really useful when we want to reuse a class for different types and with constraints on what those types would be without rewriting those classes. C# allows at least 5 different kinds of Generics usage as related to the kind of constraints that we can use plus the most basic implementations such…

We generally apply the concept of inheritance to implement a IS-A relationship. For example to implement a relationship that says an Apple is a Fruit or Earth is a cosmic object. We use inheritance very carefully so that it does not lead to long complex/un-maintainable object hierarchies, but to implement very specific object hierarchies with…

Interface is a similar language construct such as class, but fundamentally different from a class. Some people claim that Interface is a way to implement multiple inheritance – this claim is also not true! If we were to implement inheritance via interfaces, then we would have re-used, but there is no code reuse while implementing…

We use abstract classes when the base class can’t have concrete implementation and that we need the derived class to fully implement it. If at least one of the member is abstract, then the class will need to be declared as abstract. If a class derives an abstract class, then it needs to override all…

Below is a simple stop watch implemented in C#, enjoy!StopWatch using System; namespace StopWatchApp {     public class StopWatch     {         public DateTime StarTime { get; set; }         public DateTime StopTime { get; set; }         public string ClockState { get; set; }         public void StartClock()         {             if(this.ClockState == “started”)                 throw new InvalidOperationException(“Invalid Operation”);             this.StarTime = DateTime.Now;             this.ClockState = “started”;         }         public void StopClock()         {             this.StopTime = DateTime.Now;             this.ClockState = “stopped”;         }         public TimeSpan ElapsedTime()         {             return this.StopTime – this.StarTime;         }     }  } Main Program using System; namespace StopWatchApp {     public class Program     {         public static void Main(string[] args)         {             Console.WriteLine(“Enter Start to Start the Clock,  Enter Stop to Stop the Clock to see the elapsed time.  Enter Quit to exit.”);             var clock = new StopWatch();             int alreadystarted = 0;             while (true)             {                 var inp = Console.ReadLine();                                 if (inp != “Quit”)                 {…

Lambda expressions are anonymous methods that does not have access modifiers, name or a return. They are used for convenience (less code) and makes code more readable. Lambda expression takes the form below – arg => expression //spelled as argument goes to expression This can be used in 3 distinct ways as below – ()…