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==Add a constructor to Building==

<source lang="csharp">
/*
C#: The Complete Reference
by Herbert Schildt
Publisher: Osborne/McGraw-Hill (March 8, 2002)
ISBN: 0072134852
*/
// Add a constructor to Building.

using System;

class Building {
public int floors; // number of floors
public int area; // total square footage of building
public int occupants; // number of occupants

public Building(int f, int a, int o) {
floors = f;
area = a;
occupants = o;
}

// Display the area per person.
public int areaPerPerson() {
return area / occupants;
}

/* Return the maximum number of occupants if each
is to have at least the specified minum area. */
public int maxOccupant(int minArea) {
return area / minArea;
}
}

// Use the parameterized Building constructor.
public class BuildingDemo21 {
public static void Main() {
Building house = new Building(2, 2500, 4);
Building office = new Building(3, 4200, 25);

Console.WriteLine("Maximum occupants for house if each has " +
300 + " square feet: " +
house.maxOccupant(300));

Console.WriteLine("Maximum occupants for office if each has " +
300 + " square feet: " +
office.maxOccupant(300));
}
}

</source>

==Add a constructor to Triangle==

<source lang="csharp">
/*
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());
}
}

</source>

==Add constructors to TwoDShape==

<source lang="csharp">
/*
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());
}
}

</source>

==Add more constructors to TwoDShape==

<source lang="csharp">
/*
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();
}
}

</source>

==A parameterized constructor==

<source lang="csharp">
/*
C#: The Complete Reference
by Herbert Schildt
Publisher: Osborne/McGraw-Hill (March 8, 2002)
ISBN: 0072134852
*/
// A parameterized constructor.

using System;

class MyClass {
public int x;

public MyClass(int i) {
x = i;
}
}

public class ParmConsDemo {
public static void Main() {
MyClass t1 = new MyClass(10);
MyClass t2 = new MyClass(88);

Console.WriteLine(t1.x + " " + t2.x);
}
}

</source>

==A simple constructor==

<source lang="csharp">
/*
C#: The Complete Reference
by Herbert Schildt
Publisher: Osborne/McGraw-Hill (March 8, 2002)
ISBN: 0072134852
*/
// A simple constructor.

using System;

class MyClass {
public int x;

public MyClass() {
x = 10;
}
}

public class ConsDemo1 {
public static void Main() {
MyClass t1 = new MyClass();
MyClass t2 = new MyClass();

Console.WriteLine(t1.x + " " + t2.x);
}
}

</source>

==C# Class Constructor Overloading==

<source lang="csharp">
public Overloading
{
public static void Main()
{
Point myPoint = new Point(10, 15);
Point mySecondPoint = new Point(myPoint);
}
}
class Point
{
// create a new point from x and y values
public Point(int x, int y)
{
this.x = x;
this.y = y;
}
// create a point from an existing point
public Point(Point p)
{
this.x = p.x;
this.y = p.y;
}

int x;
int y;
}

</source>

==Check the parameter in construtor==

<source lang="csharp">
using System;
public class Class1 {
public static void Main(string[] args) {
Student student = new Student("AAA", 1234);
Console.WriteLine("Welcome new student {0}", student.GetString());
}
}
public class Student {
string sStudentName;
int nStudentID;
int nCreditHours;
public Student(string sName, int nID) {
if (sName == null) {
sName = "invalid";
}
sStudentName = sName;
if (nID < 0) {
nID = 0;
}
nStudentID = nID;
nCreditHours = 0;
}
public string GetString() {
string s = String.Format("{0}({1})",sStudentName, nStudentID);
return s;
}
}
</source>

==constructor initializers are called bottom-up but the constructors are invoked top-down starting with the constructor in the base class==

<source lang="csharp">
using System;
public class Starter {
public static void Main() {
XClass obj = new XClass();
}
}
public class MyClass {
public MyClass(int param) {
Console.WriteLine("MyClass constructor");
}
}
public class YClass : MyClass {
public YClass(int param) : base(YClass.MethodA()) {
Console.WriteLine("YClass constructor");
}
public static int MethodA() {
Console.WriteLine("YClass constructor initializer");
return 0;
}
}
public class XClass : YClass {
public XClass() : base(XClass.MethodA()) {
Console.WriteLine("XClass constructor");
}
public static new int MethodA() {
Console.WriteLine("XClass constructor initializer");
return 0;
}
}
</source>

==Constructor overloading 3==

<source lang="csharp">
/*
* 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;
}
}
}

</source>

==Demonstrate an overloaded constructor==

<source lang="csharp">
/*
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);
}
}

</source>

==Demonstrate invoking a constructor through this==

<source lang="csharp">
/*
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);
}
}

</source>

==Illustrates a copy constructor==

<source lang="csharp">
/*
Mastering Visual C# .NET
by Jason Price, Mike Gunderloy
Publisher: Sybex;
ISBN: 0782129110
*/
/*
Example5_13.cs illustrates a copy constructor
*/

// declare the Car class
class Car
{
// declare the fields
private string make;
private string model;
private string color;
private int yearBuilt;
// define the copy constructor
public Car(Car car)
{
this.make = car.make;
this.model = car.model;
this.color = car.color;
this.yearBuilt = car.yearBuilt;
}
public Car(string make, string model, string color, int yearBuilt)
{
this.make = make;
this.model = model;
this.color = color;
this.yearBuilt = yearBuilt;
}
// define method to display the fields
public void Display()
{
System.Console.WriteLine("make = " + make);
System.Console.WriteLine("model = " + model);
System.Console.WriteLine("color = " + color);
System.Console.WriteLine("yearBuilt = " + yearBuilt);
}
}

public class Example5_13
{
public static void Main()
{
// create a Car object
Car myCar = new Car("Toyota", "MR2", "black", 1995);
// create a copy of this Car object
Car carCopy = new Car(myCar);
// display the values for the Car object"s fields
System.Console.WriteLine("myCar details:");
myCar.Display();
System.Console.WriteLine("carCopy details:");
carCopy.Display();
}
}

</source>

==Illustrates how to define a constructor==

<source lang="csharp">
/*
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();
}
}

</source>

==Illustrates overloaded constructors==

<source lang="csharp">
/*
Mastering Visual C# .NET
by Jason Price, Mike Gunderloy
Publisher: Sybex;
ISBN: 0782129110
*/

/*
Example5_12.cs illustrates overloaded constructors
*/

// declare the Car class
class Car
{
// declare the fields
private string make;
private string model;
private string color;
private int yearBuilt;
// define the overloaded constructors
public Car()
{
this.make = "Ford";
this.model = "Mustang";
this.color = "red";
this.yearBuilt = 1970;
}
public Car(string make)
{
this.make = make;
this.model = "Corvette";
this.color = "silver";
this.yearBuilt = 1969;
}
public Car(string make, string model, string color, int yearBuilt)
{
this.make = make;
this.model = model;
this.color = color;
this.yearBuilt = yearBuilt;
}
// define method to display the fields
public void Display()
{
System.Console.WriteLine("make = " + make);
System.Console.WriteLine("model = " + model);
System.Console.WriteLine("color = " + color);
System.Console.WriteLine("yearBuilt = " + yearBuilt);
}
}

public class Example5_12
{
public static void Main()
{
// create three Car objects using the constructors
// defined in the class
Car myCar = new Car("Toyota", "MR2", "black", 1995);
Car myCar2 = new Car();
Car myCar3 = new Car("Chevrolet");
// display the values for the Car object"s fields
System.Console.WriteLine("myCar details:");
myCar.Display();
System.Console.WriteLine("myCar2 details:");
myCar2.Display();
System.Console.WriteLine("myCar3 details:");
myCar3.Display();
}
}

</source>

==Shows the order in which constructors and destructors are called in a C# program==

<source lang="csharp">
/*
C# Programming Tips & Techniques
by Charles Wright, Kris Jamsa
Publisher: Osborne/McGraw-Hill (December 28, 2001)
ISBN: 0072193794
*/
// Order.cs - shows the order in which constructors and destructors
// are called in a C# program.
//
// Compile this program with the following command line:
// C:>csc Order.cs
//
namespace nsOrder
{
using System;

public class clsMainOrder
{
static public void Main ()
{
clsLastChild child = new clsLastChild ();
Console.WriteLine ();
}
}
//
// Declare a base class and have its constructor and destructors
// print messages.
class clsBase
{
public clsBase ()
{
Console.WriteLine ("Base class constructor called");
}
~clsBase ()
{
Console.WriteLine ("Base class destructor called");
}
}
// Derive a class from clsBase. Have the constructor and destructor
// print messages.
class clsFirstChild : clsBase
{
public clsFirstChild ()
{
Console.WriteLine ("First Child constructor called");
}
~clsFirstChild ()
{
Console.WriteLine ("First Child destructor called");
}
}
// Derive a class from clsFirstChile. Have the constructor and destructor
// print messages as well.
class clsLastChild : clsFirstChild
{
public clsLastChild ()
{
Console.WriteLine ("Last Child constructor called");
}
~clsLastChild ()
{
Console.WriteLine ("Last Child destructor called");
}
}
}

</source>

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