C # Language Primer (3)

In this last example, we look at the abstraction and polymorphism of C #. Let's start by defining these two new terms. Abstract is implemented by extracting the common parts from multiple objects and merging them into a separate abstract class. In this example we will create an abstract class shape (shape). Each shape has a method of returning its color, whether it is a square or a circle or a rectangle, and the method of returning the color is always the same, so this method can be extracted into the parent shape. So, if we have 10 different shapes that need a way to return the color, now we just have to create a method in the parent class. You can see using abstractions to make your code shorter.

In the field of object-oriented programming, polymorphism (polymorphism) is the ability of an object or method to behave differently depending on the class. In the following example, the abstract class shape has a Getarea () method that has different functions for different shapes (circles, squares, or rectangles).

Here's the code:


Public abstract class Shape {
protected string color;
Public Shape (string color) {
This.color = color;
}
public string GetColor () {
return color;
}
public abstract double Getarea ();
}

public class Circle:shape {
private double radius;
Public Circle (string color, double radius): base (color) {
This.radius = radius;
}
public override double Getarea () {
return System.Math.PI * radius * RADIUS;
}
}

public class Square:shape {
Private double Sidelen;
Public Square (string color, double Sidelen): base (color) {
This.sidelen = Sidelen;
}
public override double Getarea () {
return Sidelen * Sidelen;
}
}

/*
public class Rectangle:shape
... Slightly...
*/

public class Example3
{
static void Main ()
{
Shape mycircle = new Circle ("Orange", 3);
Shape myrectangle = new Rectangle ("Red", 8, 4);
Shape mysquare = new Square ("Green", 4);
System.Console.WriteLine ("The color of the circle is" + Mycircle.getcolor ()
+ "It's area is" + mycircle.getarea () + ".");
System.Console.WriteLine ("The color of the rectangle is" + myrectangle.getcolor ()
+ "It's area is" + myrectangle.getarea () + ".");
System.Console.WriteLine ("The color of the square is" + mysquare.getcolor ()
+ "It's area is" + mysquare.getarea () + ".");
}
}