illustrates how to use a 'has a' relationship : Class Definition : Class Interface C# Source Code

    

/*
Mastering Visual C# .NET
by Jason Price, Mike Gunderloy

Publisher: Sybex;
ISBN: 0782129110
*/
/*
  Example6_5.cs illustrates how to use a "has a"
  relationship
*/


// declare the Engine class
class Engine
{

  // declare the fields
  public int cylinders;
  public int horsepower;

  // define the method
  public void Start()
  {
    System.Console.WriteLine("Engine started");
  }

}


// declare the Car class
class Car
{

  // declare the fields
  public string make;
  public Engine engine;  // Car has an Engine

  // define the method
  public void Start()
  {
    engine.Start();
  }

}


public class Example6_5
{

  public static void Main()
  {

    // declare a Car object reference named myCar
    System.Console.WriteLine("Creating a Car object");
    Car myCar = new Car();
    myCar.make = "Toyota";

    // Car objects have an Engine object
    System.Console.WriteLine("Creating an Engine object");
    myCar.engine = new Engine();
    myCar.engine.cylinders = 4;
    myCar.engine.horsepower = 180;

    // display the values for the Car and Engine object fields
    System.Console.WriteLine("myCar.make = " + myCar.make);
    System.Console.WriteLine("myCar.engine.cylinders = " +
      myCar.engine.cylinders);
    System.Console.WriteLine("myCar.engine.horsepower = " +
      myCar.engine.horsepower);

    // call the Car object's Start() method
    myCar.Start();

  }

}