⌛ Shapes¶

Place your code into files named Circle.java, Rectangle.java and IShapeMetrics.java¹ in the directory Round6/shapes. Remember to pull student_template_project for material.

¹ Here we use the convention of naming interfaces with I-prefix. This is a common practice especially in the C# programming language, but some use it in Java too.

In this exercise you should implement the following simple interface and two classes:

• Interface IShapeMetrics that has:

  • Member variable double PI that defines pi using 5 decimals of precision.

  • Abstract memebr functions String name(), double area() and double circumference().

• Class Circle that implements the interface IShapeMetrics and stores the radius of a circle as a double. Public members:

  • Constructor Circle(double radius) that initializes the radius.

  • Member function String toString() that returns a String of form “Circle with radius: x”, where x is the radius with 2 decimals of precision.

  • Member function String name() that returns the String “circle”.

  • Member function double area() that returns the area of the circle, computed using PI as the value of pi.

  • Member function double circumference() that returns the circumference of the rectangle, computed using PI as the value of pi.

• Class Rectangle that implements the interface IShapeMetrics and stores the height and width of a rectangle as double. Public members:

  • Constructor Rectangle(double height, double width) that initilizes height and width.

  • Member function String toString() that returns a String of form “Rectangle with height x and width y”, where x is the height and y the width of the rectangle, both with 2 decimals of precision.

  • Member function String name() that returns the String “rectangle”.

  • Member function double area() that returns the area of the rectangle.

  • Member function double circumference() that returns the circumference of the rectangle.