/*
A Programmer's Introduction to C# (Second Edition)
by Eric Gunnerson

Publisher: Apress  L.P.
ISBN: 1-893115-62-3
*/
// 18 - PropertiesStatic Properties
// copyright 2000 Eric Gunnerson
class Color
{
    public Color(int red, int green, int blue)
    {
        this.red = red;
        this.green = green;
        this.blue = blue;
    }
    
    int    red;
    int    green;
    int    blue;
    
    public static Color Red
    {
        get
        {
            return(new Color(255, 0, 0));
        }
    }
    public static Color Green
    {
        get
        {
            return(new Color(0, 255, 0));
        }
    }
    public static Color Blue
    {
        get
        {
            return(new Color(0, 0, 255));
        }
    }
}

public class StaticProperties
{
    static void Main()
    {
        Color background = Color.Red;
    }
}

           
          

/*
A Programmer's Introduction to C# (Second Edition)
by Eric Gunnerson

Publisher: Apress L.P.
ISBN: 1-893115-62-3
*/

// 22 – DelegatesDelegates as Static Properties
// copyright 2000 Eric Gunnerson
using System;
class Container
{
public delegate int CompareItemsCallback(object obj1, object obj2);
public void SortItems(CompareItemsCallback compare)
{
// not a real sort, just shows what the
// inner loop code might do
int x = 0;
int y = 1;
object item1 = arr[x];
object item2 = arr[y];
int order = compare(item1, item2);
}
object[] arr; // items in the collection
}
class Employee
{
Employee(string name, int id)
{
this.name = name;
this.id = id;
}
public static Container.CompareItemsCallback SortByName
{
get
{
return(new Container.CompareItemsCallback(CompareName));
}
}
public static Container.CompareItemsCallback SortById
{
get
{
return(new Container.CompareItemsCallback(CompareId));
}
}
static int CompareName(object obj1, object obj2)
{
Employee emp1 = (Employee) obj1;
Employee emp2 = (Employee) obj2;
return(String.Compare(emp1.name, emp2.name));
}
static int CompareId(object obj1, object obj2)
{
Employee emp1 = (Employee) obj1;
Employee emp2 = (Employee) obj2;

if (emp1.id > emp2.id)
return(1);
if (emp1.id < emp2.id) return(-1); else return(0); } string name; int id; } public class DelegatesasStaticProperties { public static void Main() { Container employees = new Container(); // create and add some employees here employees.SortItems(Employee.SortByName); // employees is now sorted by name } } [/csharp]

   


/*
A Programmer's Introduction to C# (Second Edition)
by Eric Gunnerson

Publisher: Apress  L.P.
ISBN: 1-893115-62-3
*/
// 18 - PropertiesAccessors
// copyright 2000 Eric Gunnerson

public class PropertiesAccessors
{
    private string name;
    
    public string Name
    {
        get 
        {
            return name;
        }
        set 
        {
            name = value;
        }
    }
}

           
          

   


/*
A Programmer's Introduction to C# (Second Edition)
by Eric Gunnerson

Publisher: Apress  L.P.
ISBN: 1-893115-62-3
*/
// 18 - PropertiesSide Effects When Setting Values
// copyright 2000 Eric Gunnerson
using System;
using System.Collections;
class Basket
{
    internal void UpdateTotal()
    {
        total = 0;
        foreach (BasketItem item in items)
        {
            total += item.Total;
        }
    }
    
    ArrayList    items = new ArrayList();
    Decimal    total;
}
public class BasketItem
{
    BasketItem(Basket basket)
    {
        this.basket = basket;
    }
    public int Quantity
    {
        get
        {
            return(quantity);
        }
        set
        {
            quantity = value;
            basket.UpdateTotal();
        }
    }
    public Decimal Price
    {
        get
        {
            return(price);
        }
        set
        {
            price = value;
            basket.UpdateTotal();
        }
    }
    public Decimal Total
    {
        get
        {
            // volume discount; 10% if 10 or more are purchased
            if (quantity >= 10)
            return(quantity * price * 0.90m);
            else
            return(quantity * price); 
        }
    }
    
    int        quantity;     // count of the item
    Decimal    price;        // price of the item
    Basket     basket;       // reference back to the basket
}

           
          

   


/*
A Programmer's Introduction to C# (Second Edition)
by Eric Gunnerson

Publisher: Apress  L.P.
ISBN: 1-893115-62-3
*/
// 18 - PropertiesUse of Properties
// copyright 2000 Eric Gunnerson
using System;
public class Auto
{
    public Auto(int id, string name)
    {
        this.id = id;
        this.name = name;
    }
    
    // query to find # produced
    public int ProductionCount
    {
        get
        {
            if (productionCount == -1)
            {
                // fetch count from database here.
            }
            return(productionCount);
        }
    }
    public int SalesCount
    {
        get
        {
            if (salesCount == -1)
            {
                // query each dealership for data
            }
            return(salesCount);
        }
    }
    string name;
    int id;
    int productionCount = -1;
    int salesCount = -1;
}

           
          

/*
C# Programming Tips & Techniques
by Charles Wright, Kris Jamsa

Publisher: Osborne/McGraw-Hill (December 28, 2001)
ISBN: 0072193794
*/
//
// Property.cs — Demonstrates access to a private field through a property.
// Compile this program with the following command line:
// C:>csc Property.cs
//
namespace nsProperty
{
using System;
public class Property
{
const double radian = 57.29578;
const double pi = 3.14159;
int Angle
{
get
{
int angle = (int) (fAngle * radian + 0.5);
angle = angle == 360 ? 0 : angle;
return (angle);
}
set
{
double angle = (double) value / radian;
if (angle < (2 * pi)) { fAngle = angle; Console.WriteLine ("fAngle set to {0,0:F5}", fAngle); } else { Console.WriteLine ("fAngle not modified"); } } } double fAngle = 0.0; // Angle in radians static public int Main (string [] args) { int angle; try { angle = int.Parse (args[0]); } catch (IndexOutOfRangeException) { Console.WriteLine ("usage: circle [angle in degrees]"); return (-1); } catch (FormatException) { Console.WriteLine ("Please use a number value for the angle in degrees"); return (-1); } Property main = new Property(); main.Angle = angle; Console.WriteLine ("The angle is {0} degrees", main.Angle); return (0); } } } [/csharp]

   

/*
C# Programming Tips & Techniques
by Charles Wright, Kris Jamsa

Publisher: Osborne/McGraw-Hill (December 28, 2001)
ISBN: 0072193794
*/

//
// Abstract.cs -- Demonsrates the use of an abstract property.
//
//                Compile this program with the following command line:
//                    C:>csc Abstract.cs
//
namespace nsAbstract
{
    using System;
    using System.Runtime.InteropServices;
    public class AbstractPro
    {
        static public void Main ()
        {
            Console.WriteLine (clsAbstract.StaticMethod());
        }
    }
    //
    // To use the abstract modifier on a method, the class also must
    // be declared as abastract
    abstract class clsAbstract
    {
    //
    // To declare an abstract method, end the declaration with a semicolon.
    // Do not provide a body for the method.
        abstract public int AbstractMethod();
    //
    // An abstract class may contain a static method. You do not have
    // to declare an instance of the class to access a static method
        static public double StaticMethod()
        {
            return (3.14159 * 3.14159);
        }
        abstract public long Prop
        {
            get;
            set;
        }
    }
    //
    // Inherit from the abstract class. The following class implements
    // the AbstractMethod().
    // The access level of the derived class method must be the same
    // as the access level of the base class abstract method.
    class clsDerivedFromAbstract : clsAbstract
    {
        override public int AbstractMethod()
        {
            return (0);
        }
        override public long Prop
        {
            get
            {
                return (val);
            }
            set
            {
                val = value;
            }
        }
        private long val;
    }
}