Illustrates the use of a property

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


   

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

Publisher: Sybex;
ISBN: 0782129110
*/
/*
  Example6_4.cs illustrates the use of a property
*/


// declare the Car class
class Car
{

  // declare a private field
  private string make;

  // declare a property
  public string Make
  {
    get
    {
      return make;
    }
    set
    {
      make = value;
    }
  }

}


public class Example6_4
{

  public static void Main()
  {

    // create a Car object
    System.Console.WriteLine("Creating a Car object");
    Car myCar = new Car();

    // set the Car Make
    System.Console.WriteLine("Setting the Car object&#039;s Make property to Porsche");
    myCar.Make = "Porsche";

    System.Console.WriteLine("myCar.Make = " + myCar.Make);

  }

}

Demonstrates the use of properties to control how values are saved in fields

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


   

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

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

//  Rect.cs - Demonstrates the use of properties to control how values are
//            saved in fields
//
//            This is a Visual Studio project. To compile outside of Visual
//            Studio, use the following command line:
//                C:>csc rect.cs
//
using System;
using System.Drawing;

namespace nsRect
{
  struct POINT
  {
    public POINT (int x, int y)
    {
      this.cx = x;
      this.cy = y;
    }
    public int cx;
    public int cy;
    public override string ToString ()
    {
      return (String.Format ("({0}, {1})", cx, cy));
    }
  }
  struct RECT
  {
    public RECT (Rectangle rc)
    {
      m_UpperLeft.cx = rc.X;
      m_UpperLeft.cy = rc.Y;
      m_LowerRight.cx = rc.X + rc.Width;
      m_LowerRight.cy = rc.Y + rc.Height;
    }
    // Define constructors
    public RECT (POINT pt1, POINT pt2)
    {
      m_UpperLeft = pt1;
      m_LowerRight = pt2;
    }
    public RECT (int x1, int y1, int x2, int y2)
    {
      m_UpperLeft.cx = x1;
      m_UpperLeft.cy = y1;
      m_LowerRight.cx = x2;
      m_LowerRight.cy = y2;
    }
    public RECT (POINT pt1, int Width, int Height)
    {
      m_UpperLeft.cx = pt1.cx;
      m_UpperLeft.cy = pt1.cy;
      m_LowerRight.cx = pt1.cx + Width;
      m_LowerRight.cy = pt1.cy + Height;
    }
    // Property to get and set the upper left point
    public POINT UpperLeft
    {
      get {return (m_UpperLeft);}
      set {m_UpperLeft = value;}
    }
    // Property to get and set the lower right point
    public POINT LowerRight
    {
      get {return (m_LowerRight);}
      set {m_LowerRight = value;}
    }
    // Property to return a normalized System.Drawing.ectangle object
    public System.Drawing.Rectangle Rectangle
    {
      get
      {
        RECT rc = Normal;
        return (new Rectangle (rc.UpperLeft.cx, rc.UpperLeft.cy,
          rc.LowerRight.cx - rc.UpperLeft.cx,
          rc.LowerRight.cy - rc.UpperLeft.cy));
      }
    }
    // Property to return a normalized copy of this rectangle
    public RECT Normal
    {
      get
      {
        return (new RECT (
          Math.Min (m_LowerRight.cx, m_UpperLeft.cx),
          Math.Min (m_LowerRight.cy, m_UpperLeft.cy),
          Math.Max (m_LowerRight.cx, m_UpperLeft.cx),
          Math.Max (m_LowerRight.cy, m_UpperLeft.cy))
          );

      }
    }
    private POINT m_UpperLeft;
    private POINT m_LowerRight;
    public override string ToString()
    {
      return (String.Format ("Upper left = {0}; Lower right = {1}",
        m_UpperLeft, m_LowerRight));
    }
  }
  public class Rect
  {
    static public void Main ()
    {
      // Define a "normal" rectangle
      POINT pt1 = new POINT (-10,30);
      POINT pt2 = new POINT (100, 100);
      RECT rc = new RECT (pt1, pt2);
      Console.WriteLine ("RECT: " + rc);
      Console.WriteLine ("Normal: " + rc.Normal);
      Console.WriteLine ("Rectangle: " + rc.Rectangle + "
");
      // Define a rectangle with normal x but not y
      pt1.cx = 100;
      pt1.cy = 50;
      pt2.cx = 200;
      pt2.cy = 20;
      rc.UpperLeft = pt1;
      rc.LowerRight = pt2;
      Console.WriteLine ("RECT: " + rc);
      Console.WriteLine ("Normal: " + rc.Normal);
      Console.WriteLine ("Rectangle: " + rc.Rectangle + "
");
      // Define a rectangle with normal y but not x
      pt1.cx = 200;
      pt1.cy = 50;
      pt2.cx = 100;
      pt2.cy = 80;
      rc.UpperLeft = pt1;
      rc.LowerRight = pt2;
      Console.WriteLine ("RECT: " + rc);
      Console.WriteLine ("Normal: " + rc.Normal);
      Console.WriteLine ("Rectangle: " + rc.Rectangle + "
");
      // Define a rectangle with both values of upper left greater than the lower y
      pt1.cx = 225;
      pt1.cy = 180;
      pt2.cx = 25;
      pt2.cy = 35;
      rc.UpperLeft = pt1;
      rc.LowerRight = pt2;
      Console.WriteLine ("RECT: " + rc);
      Console.WriteLine ("Normal: " + rc.Normal);
      Console.WriteLine ("Rectangle: " + rc.Rectangle + "
");
      // Define a rectangle with points equal
      pt1.cx = 75;
      pt1.cy = 150;
      pt2.cx = 75;
      pt2.cy = 150;
      rc.UpperLeft = pt1;
      rc.LowerRight = pt2;
      Console.WriteLine ("RECT: " + rc);
      Console.WriteLine ("Normal: " + rc.Normal);
      Console.WriteLine ("Rectangle: " + rc.Rectangle + "
");
    }
  }
}

Define properties for class

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


   

/*
Learning C# 
by Jesse Liberty

Publisher: O&#039;Reilly 
ISBN: 0596003765
*/
 using System;

 namespace Properties
 {
     class Time
     {

         // private member variables
         private int year;
         private int month;
         private int date;
         private int hour;
         private int minute;
         private int second;

         // create a property
         public int Hour
         {
             get
             {
                 return hour;
             }

             set
             {
                 hour = value;
             }
         }

         // public accessor methods
         public void DisplayCurrentTime()
         {
             System.Console.WriteLine(
                 "Time: {0}/{1}/{2} {3}:{4}:{5}",
                 month, date, year, hour, minute, second);
         }


         // constructors
         public Time(System.DateTime dt)
         {
             year =      dt.Year;
             month =     dt.Month;
             date =      dt.Day;
             hour =      dt.Hour;
             minute =    dt.Minute;
             second =    dt.Second;
         }


    }
    public class PropertiesTester
    {
       public void Run()
       {
           System.DateTime currentTime = System.DateTime.Now;
           Time t = new Time(currentTime);
           t.DisplayCurrentTime();

           // access the hour to a local variable
           int theHour = t.Hour;

           // display it
           System.Console.WriteLine("Retrieved the hour: {0}",
               theHour);

           // increment it
           theHour++;

           // reassign the incremented value back through
           // the property
           t.Hour = theHour;

           // display the property
           System.Console.WriteLine("Updated the hour: {0}", t.Hour);
       }

       [STAThread]
       static void Main()
       {
          PropertiesTester t = new PropertiesTester();
          t.Run();
       }
    }
 }

Use properties to set and get private members

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
*/


// Use properties to set and get private members. 
 
using System; 
 
// A class for two-dimensional objects. 
class TwoDShape { 
  double pri_width;  // now private 
  double pri_height; // now private  
 
  // Properties for width and height. 
  public double width { 
     get { return pri_width; } 
     set { pri_width = value; } 
  } 
 
  public double height { 
     get { return pri_height; } 
     set { pri_height = value; } 
  } 
 
  public void showDim() { 
    Console.WriteLine("Width and height are " + 
                       width + " and " + height); 
  } 
} 
 
// A derived class of TwoDShape for triangles. 
class Triangle : TwoDShape { 
  public string style; // style of triangle 
   
  // Return area of triangle. 
  public double area() { 
    return width * height / 2;  
  } 
 
  // Display a triangle&#039;s style. 
  public void showStyle() { 
    Console.WriteLine("Triangle is " + style); 
  } 
} 
 
public class Shapes2 { 
  public static void Main() { 
    Triangle t1 = new Triangle(); 
    Triangle t2 = new Triangle(); 
 
    t1.width = 4.0; 
    t1.height = 4.0; 
    t1.style = "isosceles"; 
 
    t2.width = 8.0; 
    t2.height = 12.0; 
    t2.style = "right"; 
 
    Console.WriteLine("Info for t1: "); 
    t1.showStyle(); 
    t1.showDim(); 
    Console.WriteLine("Area is " + t1.area()); 
 
    Console.WriteLine(); 
 
    Console.WriteLine("Info for t2: "); 
    t2.showStyle(); 
    t2.showDim(); 
    Console.WriteLine("Area is " + t2.area()); 
  } 
}

Error handling in property setter validating

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

   
 


using System;

public class Employee {
    private int prop_age;
    public int age {
        set {
            if (value < 0 || value > 120) {
                throw new ApplicationException("Not valid age!");
            }
            prop_age = value;
        }
        get {
            return prop_age;
        }
    }
}

Convert errflag into a property

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
*/

// Convert errflag into a property.

using System;

class FailSoftArray {
int[] a; // reference to underlying array
int len; // length of array

bool errflag; // now private

// Construct array given its size.
public FailSoftArray(int size) {
a = new int[size];
len = size;
}

// Read-only Length property.
public int Length {
get {
return len;
}
}

// Read-only Error property.
public bool Error {
get {
return errflag;
}
}

// This is the indexer for FailSoftArray.
public int this[int index] {
// This is the get accessor.
get {
if(ok(index)) {
errflag = false;
return a[index];
} else {
errflag = true;
return 0;
}
}

// This is the set accessor
set {
if(ok(index)) {
a[index] = value;
errflag = false;
}
else errflag = true;
}
}

// Return true if index is within bounds.
private bool ok(int index) {
if(index >= 0 & index < Length) return true; return false; } } // Demonstrate the improved fail-soft array. public class FinalFSDemo { public static void Main() { FailSoftArray fs = new FailSoftArray(5); // use Error property for(int i=0; i < fs.Length + 1; i++) { fs[i] = i*10; if(fs.Error) Console.WriteLine("Error with index " + i); } } } [/csharp]

Add Length property to FailSoftArray

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
*/

// Add Length property to FailSoftArray.

using System;

class FailSoftArray {
int[] a; // reference to underlying array
int len; // length of array — underlies Length property

public bool errflag; // indicates outcome of last operation

// Construct array given its size.
public FailSoftArray(int size) {
a = new int[size];
len = size;
}

// Read-only Length property.
public int Length {
get {
return len;
}
}

// This is the indexer for FailSoftArray.
public int this[int index] {
// This is the get accessor.
get {
if(ok(index)) {
errflag = false;
return a[index];
} else {
errflag = true;
return 0;
}
}

// This is the set accessor
set {
if(ok(index)) {
a[index] = value;
errflag = false;
}
else errflag = true;
}
}

// Return true if index is within bounds.
private bool ok(int index) {
if(index >= 0 & index < Length) return true; return false; } } // Demonstrate the improved fail-soft array. public class ImprovedFSDemo { public static void Main() { FailSoftArray fs = new FailSoftArray(5); int x; // can read Length for(int i=0; i < fs.Length; i++) fs[i] = i*10; for(int i=0; i < fs.Length; i++) { x = fs[i]; if(x != -1) Console.Write(x + " "); } Console.WriteLine(); // fs.Length = 10; // Error, illegal! } } [/csharp]

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