Lists and Hypertexh
Ordered Lists:
beginol
point (one)
point (two)
endol
|
Unordered Lists:
beginul
point (one)
point (two)
endul
|
Definition
CLASSIFICATION is the process of grouping objects having like properties (structure and behavior) into sets.
Definition
A CLASS is a set of objects grouped together as a result of classifications.
Definition
An INSTANCE of a class is an individual element of a class.
Definition
An OBJECT, in the abstract, is a collection of ``parts, '' ``behaviors, '' and ``relations.''
Definition
An OBJECT, for practical programming purposes, is either a class or an instance of a class.
Definition
A STATIC OBJECT is another term used to refer to a class.
Definition
A DYNAMIC OBJECT is another term used to refer to an instance of a class.
The Circle Class
Using ``shapes world, '' a conceptual entity consisting of circles, squares, rectangles, triangles, and polygons, we will create and use objects (also known as scripting).
CIRCLE CLASS
newCircle (< double >) -- < circle >
This program is used to create a new circle whose radius is the given number.
< circle > .radius () -- < double >
Compute the radius of the given circle.
< circle > .diameter () -- < double >
Compute the diameter of the circle.
< circle > .area () -- < double >
Compute the area of the circle.
< circle > .perimeter () -- < double >
Compute the perimeter of the circle.
< circle > .describe ()
Describes the circle.
< circle > .expand (< double >)
Increases the radius of the circle by the given number.
< circle > .shrink (< double >)
Decreases the radius of the circle by the given number.
|
TASKS:
Suppose c and d have been bound to circles.
/ /Display the area of circle c.
IO.println (c.area ());
/ /Declare a variable called average and bind it to the
average value of the radii of the two circles.
double avg = (c.radius () + d.radius ()) / 2.0;
/ /Expand circle d by adding 10 to its radius.
d.expand (10);
/ /Display the area of a circle of radius 15..
Circle clara = new Circle (15);
double areaOfClara = clara.area ();
IO.println (areaOfClara);
|
Problem
A circular garden of diameter 58.2 meters is surrounded by a 2 meter brick walkway. What is the area of the walkway?
This is the solution to the problem using problem decomposition and the circle class.
? class--WalkwayApp
? needs--import blue.shapes. *;
? program
/ /Record the given information.
double diameterOfGarden = 58.2;
double walkwayWidth = 2.0;
/ /Create the garden.
double radiusOfGarden = (diameterOfGarden / 2.0);
Circle garden = new Circle (radiusOfGarden);
/ /Create the ``extended garden.''
double radiusOfXGarden = (radiusOfGarden +
walkwayWidth);
Circle xgarden = new Circle (radiusOfXGarden);
/ /Compute the area of the walkway.
double wwArea = xgarden.area () - garden.area ();
/ /Display the result.
IO.print (``The area is ``);
(wwArea);
|
