Illustrates how to define a constructor


   

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

Publisher: Sybex;
ISBN: 0782129110
*/

/*
  Example5_11.cs illustrates how to define a constructor
*/


// declare the Car class
class Car
{

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

  // define the constructor
  public Car(string make, string model, string color, int yearBuilt)
  {
    System.Console.WriteLine("In Car() constructor");
    this.make = make;
    this.model = model;
    this.color = color;
    this.yearBuilt = yearBuilt;
  }

  // define a method to display the fields
  public void Display()
  {
    System.Console.WriteLine("Car details:");
    System.Console.WriteLine("make = " + make);
    System.Console.WriteLine("model = " + model);
    System.Console.WriteLine("color = " + color);
    System.Console.WriteLine("yearBuilt = " + yearBuilt);
  }

}


public class Example5_11
{

  public static void Main()
  {

    // create a Car object using the constructor
    // defined in the class
    Car myCar = new Car("Toyota", "MR2", "black", 1995);

    // display the values for the Car object fields
    myCar.Display();

  }

}

           
          


Demonstrate invoking a constructor through this


   

/*
C#: The Complete Reference 
by Herbert Schildt 

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


// Demonstrate invoking a constructor through this. 
  
using System;  
  
class XYCoord {   
  public int x, y;   
   
  public XYCoord() : this(0, 0) { 
    Console.WriteLine("Inside XYCoord()"); 
  }  
 
  public XYCoord(XYCoord obj) : this(obj.x, obj.y) { 
    Console.WriteLine("Inside XYCoord(obj)"); 
  }  
 
  public XYCoord(int i, int j) {  
    Console.WriteLine("Inside XYCoord(int, int)"); 
    x = i; 
    y = j; 
  }     
}     
     
public class OverloadConsDemo1 {     
  public static void Main() {     
    XYCoord t1 = new XYCoord();   
    XYCoord t2 = new XYCoord(8, 9);   
    XYCoord t3 = new XYCoord(t2);   
   
    Console.WriteLine("t1.x, t1.y: " + t1.x + ", " + t1.y);  
    Console.WriteLine("t2.x, t2.y: " + t2.x + ", " + t2.y);  
    Console.WriteLine("t3.x, t3.y: " + t3.x + ", " + t3.y);  
  }     
}



           
          


Demonstrate an overloaded constructor


   

/*
C#: The Complete Reference 
by Herbert Schildt 

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


// Demonstrate an overloaded constructor. 
 
using System; 
 
class MyClass {  
  public int x;  
  
  public MyClass() { 
    Console.WriteLine("Inside MyClass()."); 
    x = 0; 
  } 
 
  public MyClass(int i) {  
    Console.WriteLine("Inside MyClass(int)."); 
    x = i;  
  } 
 
  public MyClass(double d) { 
    Console.WriteLine("Inside MyClass(double)."); 
    x = (int) d; 
  } 
 
  public MyClass(int i, int j) { 
    Console.WriteLine("Inside MyClass(int, int)."); 
    x = i * j; 
  }    
}    
    
public class OverloadConsDemo {    
  public static void Main() {    
    MyClass t1 = new MyClass();  
    MyClass t2 = new MyClass(88);  
    MyClass t3 = new MyClass(17.23);  
    MyClass t4 = new MyClass(2, 4);  
  
    Console.WriteLine("t1.x: " + t1.x); 
    Console.WriteLine("t2.x: " + t2.x); 
    Console.WriteLine("t3.x: " + t3.x); 
    Console.WriteLine("t4.x: " + t4.x); 
  }    
}


           
          


Add more constructors to TwoDShape


   

/*
C#: The Complete Reference 
by Herbert Schildt 

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


// Add more constructors to TwoDShape. 
 
using System; 
 
class TwoDShape { 
  double pri_width;  // private 
  double pri_height; // private  
 
  // Default constructor. 
  public TwoDShape() { 
    width = height = 0.0; 
  } 
 
  // Constructor for TwoDShape. 
  public TwoDShape(double w, double h) { 
    width = w; 
    height = h; 
  } 
 
  // Construct object with equal width and height. 
  public TwoDShape(double x) { 
    width = height = x; 
  } 
 
  // 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 { 
  string style; // private 
   
  /* A default constructor. This automatically invokes 
     the default constructor of TwoDShape. */ 
  public Triangle() { 
    style = "null"; 
  } 
 
  // Constructor that takes three arguments. 
  public Triangle(string s, double w, double h) : base(w, h) { 
    style = s;  
  } 
 
  // Construct an isosceles triangle. 
  public Triangle(double x) : base(x) { 
    style = "isosceles";  
  } 
 
  // Return area of triangle. 
  public double area() { 
    return width * height / 2; 
  } 
 
  // Display a triangle's style. 
  public void showStyle() { 
    Console.WriteLine("Triangle is " + style); 
  } 
} 
 
public class Shapes5 { 
  public static void Main() { 
    Triangle t1 = new Triangle(); 
    Triangle t2 = new Triangle("right", 8.0, 12.0); 
    Triangle t3 = new Triangle(4.0); 
 
    t1 = t2; 
 
    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()); 
 
    Console.WriteLine(); 
 
    Console.WriteLine("Info for t3: "); 
    t3.showStyle(); 
    t3.showDim(); 
    Console.WriteLine("Area is " + t3.area()); 
 
    Console.WriteLine(); 
  } 
}


           
          


Add constructors to TwoDShape


   

/*
C#: The Complete Reference 
by Herbert Schildt 

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


// Add constructors to TwoDShape. 
 
using System; 
 
// A class for two-dimensional objects. 
class TwoDShape { 
  double pri_width;  // private 
  double pri_height; // private  
 
  // Constructor for TwoDShape. 
  public TwoDShape(double w, double h) { 
    width = w; 
    height = h; 
  } 
 
  // 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 { 
  string style; // private 
   
  // Call the base class constructor. 
  public Triangle(string s, double w, double h) : base(w, h) { 
    style = s;  
  } 
 
  // Return area of triangle. 
  public double area() { 
    return width * height / 2; 
  } 
 
  // Display a triangle's style. 
  public void showStyle() { 
    Console.WriteLine("Triangle is " + style); 
  } 
} 
 
public class Shapes4 { 
  public static void Main() { 
    Triangle t1 = new Triangle("isosceles", 4.0, 4.0); 
    Triangle t2 = new Triangle("right", 8.0, 12.0); 
 
    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()); 
  } 
}


           
          


Add a constructor to Triangle


   

/*
C#: The Complete Reference 
by Herbert Schildt 

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


// Add a constructor to Triangle. 
 
using System; 
 
// A class for two-dimensional objects. 
class TwoDShape { 
  double pri_width;  // private 
  double pri_height; // 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 { 
  string style; // private 
   
  // Constructor 
  public Triangle(string s, double w, double h) { 
    width = w;  // init the base class 
    height = h; // init the base class 
 
    style = s;  // init the derived class 
  } 
 
  // Return area of triangle. 
  public double area() { 
    return width * height / 2;  
  } 
 
  // Display a triangle's style. 
  public void showStyle() { 
    Console.WriteLine("Triangle is " + style); 
  } 
} 
 
public class Shapes3 { 
  public static void Main() { 
    Triangle t1 = new Triangle("isosceles", 4.0, 4.0); 
    Triangle t2 = new Triangle("right", 8.0, 12.0); 
 
    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()); 
  } 
}


           
          


Constructor overloading 3

   

/*
 * 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 CTORChapter
  {
    public int[] MyIntArray;
    public int Y;
    //Initialization can take place here
    private int ObjectCount = 0;
    static void Main(string[] args)
    {
      CTORChapter X = new CTORChapter();

      X.ObjectCount++;

      CTORChapter YY = new CTORChapter(10);
    }
    //Default CTORChapter
    CTORChapter()
    {
      MyIntArray = new int[10];
      //Do work necessary during object creation
    }
    //Overloads the CTOR allowing you to initialize Y
    CTORChapter(int myY)
    {
      Y = myY;
    }
  }
}