Learning Object-Oriented Programming

Creating instances of classes in C#

We already created instances of the simple Circle class. We just needed to use the new keyword followed by the class name, specify the required arguments enclosed in parentheses, and assign the result to a variable.

The following lines declare a public CalculateArea method within the body of the Circle class:

public double CalculateArea()
{
  return Math.PI * Math.Pow(this.radius, 2);
}

The method doesn't require arguments to be called. It returns the result of the multiplication of π by the square of the radius field value (this.radius). The following lines show a new version of the Main method. These lines create two instances of the Circle class: circle1 and circle2. The lines then display the results of calling ...