Java language Programming Basic article 13th Chapter programming exercises __ Programming

1 2 3 4/* I see a sample code in the Java core technology that fits the problem, but I want to spit it in the good trouble, full of methods of call, feel better with C write to concise it? * * * * 5 GeometricObject.java:package yo

Ngheng;
    Public abstract class Geometricobject implements comparable<geometricobject>{private String color = "white";
    private Boolean filled;

    Private Java.util.Date datecreated;
            public static Geometricobject Max (Geometricobject o1,geometricobject O2) {if (O1.getarea () > O2.getarea ())
        return O1;
    else return O2;
    } protected Geometricobject () {datecreated = new java.util.Date ();
        } protected Geometricobject (String color, Boolean filled) {datecreated = new java.util.Date ();
        This.color = color;
    this.filled = filled;
    Public String GetColor () {return color;
    public void SetColor (String color) {this.color = color;
    public Boolean isfilled () {return filled;
 } public void Setfilled (Boolean filled) {       this.filled = filled;
    Public Java.util.Date getdatecreated () {return datecreated; @Override public String toString () {return ' created on ' + datecreated + \ncolor: ' + color + ' \nfille
    D: "+ filled;

    public abstract double Getarea ();

    public abstract double getprimeter (); 
        @Override public int compareTo (Geometricobject go) {if (This.getarea () > Go.getarea ()) return 1;
        else if (This.getarea () < Go.getarea ()) return-1;
    else return 0;

}} Rectangle.java:package Yongheng;
    public class Rectangle extends geometricobject{private double width;

    private double height;
        Public Rectangle () {super ();
        width = 0;
    Height = 0;
        Public Rectangle (double width, double height) {super ();
        This.width = width;
    This.height = height; Public Rectangle (double width, double height, String cOlor, Boolean filled) {super (color,filled);
        This.width = width;
    This.height = height;
    @Override public Double Getarea () {return width*height;
    @Override public Double Getprimeter () {return (width+height) *2;

}} Main.java:package Yongheng;
Import Java.util.Scanner;
Import java.util.ArrayList;
Import Java.util.Arrays;

Import java.util.Collections; public class Main {public static void main (string[] args) {arraylist<rectangle> list = new arraylist&
        Lt;> ();
        List.add (New Rectangle (1,1));
        List.add (new Rectangle (3,4));
        List.add (New Rectangle (9,10));
        List.add (new Rectangle (3,5));
        List.add (New Rectangle (4,2));
        List.add (New Rectangle (7,8));
        List.add (New Rectangle (5,6));

        List.add (New Rectangle (2,2));

        Collections.sort (list);
        for (Rectangle obj:list) {System.out.println (Obj.getarea ());
}
    }

} 

6. Class Circle:package Yongheng;

    public class Circle {private double radius = 1.0D;
    Public Circle () {radius = 1.0D;
    Public Circle (double radius) {This.radius = radius;
    Public double Getarea () {return Math.PI * radius * RADIUS;

} class Comparable:package Yongheng; public class Comparablecircle extends Circle implements comparable<comparablecircle>{public comparablecircle ()
    {super ();
    Public comparablecircle (double radius) {super (RADIUS);
            @Override public int compareTo (Comparablecircle obj) {if (This.getarea () > Obj.getarea ()) {
        return 1;
        else if (This.getarea () < Obj.getarea ()) {return-1;
    else return 0;

}} main:package Yongheng;
        public class Main {public static void main (string[] args) {comparablecircle C1 = new Comparablecircle (2.0); ComparablecircLe C2 = new comparablecircle (3.0);
    System.out.println (C1.compareto (C2));

} 7.

Geometricobject similar to the fifth problem of the same interface colorable:package Yongheng;


public interface colorable {void Howtocolor ();}

Class Square:package Yongheng;

    public class Square extends Geometricobject implements colorable{private double side = 1.0D;
        Public Square () {super ();
    side = 1.0D;
        Public Square (double side, String color, Boolean filled) {super (color,filled);
    This.side = side;
    @Override public void Howtocolor () {System.out.println (GetColor ());
    @Override public Double Getarea () {return side*side;
    @Override public Double Getprimeter () {return side*4.0;

}} main:package Yongheng; The public class Main {//I write and ask for a bit of a do not conform to public static void Main (string[] args) {geometricobject arr[] = new GeoMet
        RICOBJECT[5];
Arr[0] = new Square (1, "white", false);        ARR[1] = new Square (2, "Blue", true);
        ARR[2] = new Square (3, "Black", true);
        ARR[3] = new Square (1, "Red", true);
        ARR[4] = new Square (1, "yellow", false);
        Square temp = null;
                for (Geometricobject Obj:arr) {if (obj instanceof square) {temp = (Square) obj;
            if (temp.isfilled ()) Temp.howtocolor ();
{8}}}}.

Class Mystack:package Yongheng;

Import java.util.ArrayList;

    public class Mystack implements cloneable{private arraylist<object> list = new arraylist<object> ();
    public Boolean IsEmpty () {return list.isempty ();
    public int GetSize () {return list.size ();
    Public Object Peek () {return list.get (List.size ()-1);
        Public Object Pop () {Object o = List.get (List.size ()-1);
        List.remove (GetSize ()-1);
    return o;
   public void push (Object o) {list.add (o); @Override public String toString () {return "stack:" + list.tostring (); @SuppressWarnings ("unchecked") @Override public Object clone () throws clonenotsupportedexception{M
        Ystack tstack = (mystack) super.clone ();
        Tstack.list = (arraylist<object>) list.clone ();
    return tstack;

}} main:package Yongheng;

Import Java.util.Date;  public class Main {public static void main (string[] args) throws clonenotsupportedexception{mystack stack =
        New Mystack ();
        for (int i = 0; i < ++i) Stack.push (i);
        Mystack Nstack = (mystack) stack.clone ();
        for (int i = 0; i < ++i) Nstack.pop ();
        System.out.println (Stack.getsize ());

    System.out.println (Nstack.getsize ());

9 class Course:package Yongheng;
    public class Course implements cloneable{private String coursename;
    Private string[] Students = new STRING[100]; Private int numberofstudents;
    Public Course (String coursename) {this.coursename = Coursename;
    public void Addstudent (String student) {students[numberofstudents++] = student;
    String[] Getstudents () {return students;
    public int getnumberofstudents () {return numberofstudents;
    Public String Getcoursename () {return coursename;
        @Override public Object Clone () {Course Course = null;
            try{course = (course) super.clone ();
            Course.coursename = Coursename;
            Course.numberofstudents = numberofstudents;
        Course.students = Students.clone ();
    The catch (Clonenotsupportedexception ex) {} return course;

}} main:package Yongheng;

Import Java.util.Date;

        public class Main {public static void main (string[] args) {Course Course = new Course ("Java");
   for (int i = 0; i < ++i)         Course.addstudent (i + "t");
        Course ct = (Course) course.clone ();
        Ct.addstudent ("Zhijun");
        System.out.println (Course.getnumberofstudents ());
    System.out.println (Ct.getnumberofstudents ());
 }
}