Java Inheritance Exercises 8

Write a Java application as required:

(1) write a rectangle class rectthat contains:

Two protected Properties: Wide width of rectangle ,height height of rectangle .

Two methods of construction:

1. A construction method with two parameters to initialize the width and height properties;

2. A construction method without parameters that initializes the rectangle to a width and height of ten.

Two methods:

method for finding rectangular areas Area ()

Method for finding the perimeter of a rectangle perimeter ()

(2) by inheriting the rect class, write a rectangular class plainrect with a definite position , which is determined by

The coordinates of the upper-left corner of the rectangle are identified, including:

Add two properties: the upper-left corner of the rectangle coordinates StartX and starty.

Two methods of construction:

A construction method with 4 parameters for StartX,starty,width , and Height Property

Initialization

Constructs without parameters, initializes the rectangle to the upper-left coordinate, the length and width are 0

the rectangle;

Add a method:

A method isinside that determines whether a point is inside a rectangle (double x,double y). As in the moment

Inside the shape, returns true, Otherwise, returns false.

Tip: A point in a rectangular class means satisfying a condition:

x>=startx&&x<= (startx+width) &&y<starty&&y>= (startY-height)

(3) writing test Procedures for Plainrect class

Create a rectangular object with the upper-left coordinate (ten,ten), and awidth of ten ;

Calculates and prints the area and perimeter of the output rectangle;

Determines whether the point (25.5) is inside the rectangle and prints out the relevant information.

 Public classRect {protected Doublewidth; protected Doubleheight; Rect (DoubleWidthDoubleheight) {         This. height=height;  This. width=width; } Rect () {width=0; Height=0; }     Public voidArea () {DoubleA; A=width*height; System.out.println ("The area of the rectangle is" +a); }     Public voidperimeter () {DoubleA; A=width*2+height*2; System.out.println ("The perimeter of the rectangle is" +a); }

 Public classPlainrectextendsRect {Private DoubleStartX; Private DoubleStarty;  Public DoubleGetstartx () {returnStartX; }     Public voidSetstartx (DoubleStartX) {         This. StartX =StartX; }     Public DoubleGetstarty () {returnStarty; }     Public voidSetstarty (Doublestarty) {         This. Starty =Starty; } plainrect (DoubleWidthDoubleHeightDoubleStartX,Doublestarty) {         This. width=width;  This. Height =height;  This. startx=StartX;  This. starty=Starty; } plainrect () {width=0; Height=0; StartX=0; Starty=0; }     Public BooleanIsinside (DoubleXDoubley) {if(x>=startx&&x<= (Startx+width) &&y<starty&&y>= (startY-height)) {            return true; }        Else        {            return false; }    }

 Public class Ceshiplainrect {    publicstaticvoid  main (string[] args) {        Plainrect p=new plainrect (10,20,10,10);        P.area ();        P.perimeter ();        System.out.println (P.isinside (25.5));}    }

Java Inheritance exercises 8