Notes

Base class or Parent class.
class Shape
{
public double Width;
public double Height;
public void ShowDim()
{
Console.WriteLine("Width and height are " +
Width + " and " + Height);
}
}
// Triangle is derived from Shape.
//Drived class or Child class.
class Triangle : Shape
{
public string Style; // style of triangle
// Return area of triangle.
public double Area()
{
return Width * Height / 2;
}
// Display a triangle's style.
public void ShowStyle()
{
Console.WriteLine("Triangle is " + Style);
}
}
//Driver class which runs the program.
class Driver
{
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());
}
}
// C# program to illustrate the
// concept of multilevel inheritance
using System;

class Shape {

double a_width;
double a_length;

// Default constructor
public Shape()
{
Width = Length = 0.0;
}

// Constructor for Shape
public Shape(double w, double l)
{
Width = w;
Length = l;
}

// Construct an object with
// equal length and width
public Shape(double y)
{
Width = Length = y;
}

// Properties for Length and Width
public double Width
{
get {
return a_width;
}

set {
a_width = value < 0 ? -value : value;
}
}

public double Length
{
get {
return a_length;
}

set {
a_length = value < 0 ? -value : value;
}
}
public void DisplayDim()
{
Console.WriteLine("Width and Length are "
+ Width + " and " + Length);
}
}

// A derived class of Shape
// for the rectangle.
class Rectangle : Shape {

string Style;

// A default constructor.
// This invokes the default
// constructor of Shape.
public Rectangle()
{
Style = "null";
}

// Constructor
public Rectangle(string s, double w, double l)
: base(w, l)
{
Style = s;
}

// Construct an square.
public Rectangle(double y)
: base(y)
{
Style = "square";
}

// Return area of rectangle.
public double Area()
{
return Width * Length;
}

// Display a rectangle's style.
public void DisplayStyle()
{
Console.WriteLine("Rectangle is " + Style);
}
}

// Inheriting Rectangle class
class ColorRectangle : Rectangle {

string rcolor;

// Constructor
public ColorRectangle(string c, string s,
double w, double l)
: base(s, w, l)
{
rcolor = c;
}

// Display the color.
public void DisplayColor()
{
Console.WriteLine("Color is " + rcolor);
}
}

// Driver Class
class GFG {

// Main Method
static void Main()
{
ColorRectangle r1 = new ColorRectangle("pink",
"Fibonacci rectangle", 2.0, 3.236);

ColorRectangle r2 = new ColorRectangle("black",
"Square", 4.0, 4.0);

Console.WriteLine("Details of r1: ");
r1.DisplayStyle();
r1.DisplayDim();
r1.DisplayColor();

Console.WriteLine("Area is " + r1.Area());
Console.WriteLine();

Console.WriteLine("Details of r2: ");
r2.DisplayStyle();
r2.DisplayDim();
r2.DisplayColor();

Console.WriteLine("Area is " + r2.Area());
}
}