Create a directory for this exercise. In this directory, create a file
named Circle.java
. In this file, define a class named Circle
, to
represent circular shapes. The class should have the features shown in
the following UML diagram:
The constructor of your class should initialize the radius
field to the
supplied value. It should NOT do any checking to see if this value
is sensible or not.
The area()
method should return the area of the circle, computed using
the radius
field. The perimeter()
method should return the circle’s
perimeter (i.e., its circumference), again using the radius
field.
Now create another file, named CircleDemo.java
, in the same directory as
Circle.java
. In this file, define a class named CircleDemo
, containing
a small program that creates a Circle
object and then calls the methods
getRadius()
, perimeter()
and area()
in turn, displaying the values
returned by these method calls. The radius for the circle can be a
hard-coded value or it can be input by the user, either via the command
line or by prompting for input and using a Scanner
or Console
object to
read it. The choice is yours!
Here’s an example of possible program output:
$ java CircleDemo
Radius = 4.5
Perimeter = 28.274
Area = 63.617
Math.PI
for the value of \(\pi\)□