Conteúdo do Curso
C# Beyond Basics
C# Beyond Basics
Practicing Polymorphism
The program given below contains a superclass called Shape
and three derived classes called Rectangle
, Square
and Circle
. The problem with the code is that the methods are not properly overridden since the output shows 0.0
for all the three Console.WriteLine
statements which implies that the methods of the base class are being executed instead of the derived class' methods.
Edit the code in such a way that the two methods, namely getArea
and calculatePerimeter
are correctly overridden.
index
using System; using System.Collections.Generic; class Shape { // Perimeter is the length of the 'outline' of a shape public float perimeter; // Change code below this line public float getArea() { return 0.0f; } protected float calculatePerimeter() { return 0.0f; } // Change code above this line } class Rectangle : Shape { float width; float height; public Rectangle(float width, float height) { this.width = width; this.height = height; this.perimeter = this.calculatePerimeter(); } // Change code below this line public float getArea() { return width * height; } protected float calculatePerimeter() { return width * 2 + height * 2; } // Change code above this line } class Square : Shape { float length; public Square(float length) { this.length = length * length; this.perimeter = calculatePerimeter(); } // Change code below this line public float getArea() { return length * length; } protected float calculatePerimeter() { return 4 * length; } // Change code above this line } class Circle : Shape { float radius; public Circle(float radius) { this.radius = radius; this.perimeter = calculatePerimeter(); } // Change code below this line public float getArea() { return 3.14f * radius * radius; } protected float calculatePerimeter() { return 2.00f * 3.14f * radius; } // Change code above this line } class ConsoleApp { static void Main() { List<Shape> shapes = new List<Shape>(); shapes.Add(new Rectangle(10f, 20f)); shapes.Add(new Square(10f)); shapes.Add(new Circle(10f)); foreach (Shape shape in shapes) { Console.WriteLine(shape.getArea()); } } }
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