illustrates how to use a 'has a' relationship

Posted on February 11, 2011June 27, 2015 by coder


   

/*
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&#039;s Start() method
    myCar.Start();

  }

}

Illustrates how to assign default values to fields using initializers

Posted on February 11, 2011June 27, 2015 by coder


   

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

Publisher: Sybex;
ISBN: 0782129110
*/
/*
  Example5_2.cs illustrates how to assign default values 
  to fields using initializers
*/


// declare the Car class
class Car
{

  // declare the fields
  public string make = "Ford";
  public string model = "T";
  public string color;  // default value of null
  public int yearBuilt = 1910;

  // define the methods
  public void Start()
  {
    System.Console.WriteLine(model + " started");
  }

  public void Stop()
  {
    System.Console.WriteLine(model + " stopped");
  }

}


public class Example5_2
{

  public static void Main()
  {

    // create a Car object
    Car myCar = new Car();

    // display the default values for the Car object fields
    System.Console.WriteLine("myCar.make = " + myCar.make);
    System.Console.WriteLine("myCar.model = " + myCar.model);
    if (myCar.color == null)
    {
      System.Console.WriteLine("myCar.color is null");
    }
    System.Console.WriteLine("myCar.yearBuilt = " + myCar.yearBuilt);

  }

}

Illustrates how to declare classes, object references, and create objects

Posted on February 11, 2011June 27, 2015 by coder


   

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

Publisher: Sybex;
ISBN: 0782129110
*/

/*
  Example5_1.cs illustrates how to declare
  classes, object references, and create objects
*/


// declare the Car class
class Car
{

  // declare the fields
  public string make;
  public string model;
  public string color;
  public int yearBuilt;

  // define the methods
  public void Start()
  {
    System.Console.WriteLine(model + " started");
  }

  public void Stop()
  {
    System.Console.WriteLine(model + " stopped");
  }

}


public class Example5_1
{

  public static void Main()
  {

    // declare a Car object reference named myCar
    Car myCar;

    // create a Car object, and assign its address to myCar
    System.Console.WriteLine("Creating a Car object and assigning " +
      "its memory location to myCar");
    myCar = new Car();

    // assign values to the Car object&#039;s fields using myCar
    myCar.make = "Toyota";
    myCar.model = "MR2";
    myCar.color = "black";
    myCar.yearBuilt = 1995;

    // display the field values using myCar
    System.Console.WriteLine("myCar details:");
    System.Console.WriteLine("myCar.make = " + myCar.make);
    System.Console.WriteLine("myCar.model = " + myCar.model);
    System.Console.WriteLine("myCar.color = " + myCar.color);
    System.Console.WriteLine("myCar.yearBuilt = " + myCar.yearBuilt);

    // call the methods using myCar
    myCar.Start();
    myCar.Stop();

    // declare another Car object reference and
    // create another Car object
    System.Console.WriteLine("Creating another Car object and " +
      "assigning its memory location to redPorsche");
    Car redPorsche = new Car();
    redPorsche.make = "Porsche";
    redPorsche.model = "Boxster";
    redPorsche.color = "red";
    redPorsche.yearBuilt = 2000;
    System.Console.WriteLine("redPorsche is a " + redPorsche.model);

    // change the object referenced by the myCar object reference
    // to the object referenced by redPorshe
    System.Console.WriteLine("Assigning redPorsche to myCar");
    myCar = redPorsche;
    System.Console.WriteLine("myCar details:");
    System.Console.WriteLine("myCar.make = " + myCar.make);
    System.Console.WriteLine("myCar.model = " + myCar.model);
    System.Console.WriteLine("myCar.color = " + myCar.color);
    System.Console.WriteLine("myCar.yearBuilt = " + myCar.yearBuilt);

    // assign null to myCar (myCar will no longer reference an object)
    myCar = null;

  }

}

Declare class and use it

Posted on February 11, 2011June 27, 2015 by coder


   

/*
C#: The Complete Reference 
by Herbert Schildt 

Publisher: Osborne/McGraw-Hill (March 8, 2002)
ISBN: 0072134852
*/
using System; 
 
class Rect { 
  public int width; 
  public int height; 
 
  public Rect(int w, int h) { 
    width = w; 
    height = h; 
  } 
 
  public int area() { 
    return width * height; 
  } 
} 
  
public class UseRect { 
  public static void Main() {   
    Rect r1 = new Rect(4, 5); 
    Rect r2 = new Rect(7, 9); 
 
    Console.WriteLine("Area of r1: " + r1.area()); 
 
    Console.WriteLine("Area of r2: " + r2.area()); 
 
  } 
}

Assign value to class

Posted on February 11, 2011June 27, 2015 by coder


   

/*
C#: The Complete Reference 
by Herbert Schildt 

Publisher: Osborne/McGraw-Hill (March 8, 2002)
ISBN: 0072134852
*/


// This program will not compile. 
 
class X { 
  int a; 
 
  public X(int i) { a = i; } 
} 
 
class Y { 
  int a; 
 
  public Y(int i) { a = i; } 
} 
 
public class IncompatibleRef { 
  public static void Main() { 
    X x = new X(10); 
    X x2;  
    Y y = new Y(5); 
 
    x2 = x; // OK, both of same type 
 
    x2 = y; // Error, not of same type 
  } 
}

Declaring Class Instances

Posted on February 11, 2011June 27, 2015 by coder

   

/*
 * C# Programmers Pocket Consultant
 * Author: Gregory S. MacBeth
 * Email: gmacbeth@comporium.net
 * Create Date: June 27, 2003
 * Last Modified Date:
 */
using System;

namespace Client.Chapter_5___Building_Your_Own_Classes
{
  public class DeclaringClassInstances
  {
    static void Main(string[] args)
    {
      ClassInstantied MyClass = new ClassInstantied();
    }
  }
  class ClassInstantied
  {
    public void Display()
    {
      Console.WriteLine("Hello World");
    }
  }
}

Declaring and Defining Classes

Posted on February 11, 2011June 27, 2015 by coder

   

/*
 * C# Programmers Pocket Consultant
 * Author: Gregory S. MacBeth
 * Email: gmacbeth@comporium.net
 * Create Date: June 27, 2003
 * Last Modified Date:
 */
using System;

namespace Client.Chapter_5___Building_Your_Own_Classes
{
  public class DeclaringandDefiningClasses
  {
    static private int MyInt = 5;
    static public int MyInt2 = 10;
    static public int[] MyIntArray;
    static private int ObjectCount = 0;
    static void Main(string[] args)
    {
      MyIntArray = new int[10];
      ObjectCount++;
    }
    public static int MyMethod(int myInt)
    {
      MyInt = MyInt + myInt;
      return MyInt;
    }
    private static long MyLongMethod(ref int myInt)
    {
      return myInt;
    }
  }
}

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