The point and rectangle of Java object-oriented exercises inheritance

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.

package rectangle;//rect class public class Rect {protected double height;protected double width; Rect () {this.width=10.0;this.height=10.0;} Rect (double height,double width) {this.width=width;this.height=height;} Public double area () {return width*height;} Public double perimeter () {return width*2+height*2;}}

　　

Package rectangle; Plainrect class public class Plainrect extends Rect {double startx;double starty; Plainrect (double startx,double starty,double width,double height) {this.startx=startx;this.starty=starty;this.width =width;this.height=height;} Plainrect () {this.startx=0;this.starty=0;this.width=0;this.height=0;} public boolean isinside (double x,double y) {if (x>=startx&&x<= (startx+width) &&y>=starty &&y<= (Starty+height)) {return true;} Else{return false;}}}

　　

Package Rectangle,//test main class public, class test {public static void main (string[] args) {plainrect j1=new plainrect (10,10,20,10); System.out.println ("The area of this rectangle is" +j1.area ()); System.out.println ("The area of this rectangle is" +j1.perimeter ()); System.out.println (J1.isinside (25.5, 13));}}

　　

Run results

The point and rectangle of Java object-oriented exercises inheritance