switch (i){
case 0: q[0] = question;
a[0] = choices[0];
a[1] = choices[1];
a[2] = choices[2];
break;
case 1: q[0] = question;
a[3] = choices[0];
a[4] = choices[1];
a[5] = choices[2];
break;
}import java.io.Serializable;
import java.util.ArrayList;
public class Question implements Serializable {
private static final long serialVersionUID = 123456789;
private String questionText;
private ArrayList<String> answers;
private String correctAnswer;
public Question(String q, ArrayList<String> a, String correctA){
questionText = q;
answers = a;
correctAnswer = correctA;
}
public String getQuestionText(){
return questionText;
}
public String getCorrectAnswer(){
return correctAnswer;
}
public String[] getAnswersArray(){
return answers.toArray(new String[answers.size()]);
}
public ArrayList<String> getAnswers(){
return answers;
}
}//make up some questions
ArrayList<String> ans = new ArrayList<String>();
ArrayList<String> ans2 = new ArrayList<String>();
ArrayList<String> ans3 = new ArrayList<String>();
ans.add("England");
ans.add("USA");
ans.add("Ireland");
ans.add("France");
Question q1 = new Question("Where was the band Led Zepplin from?", ans, "England");
ans2.add("November Rain");
ans2.add("Sweet Child o' Mine");
ans2.add("Paradise City");
ans2.add("Welcome to the Jungle");
ans2.add("Patience");
ans2.add("Live and Let Die");
Question q2 = new Question("What was Guns n' Roses first single?", ans2, "Welcome to the Jungle");
ans3.add("Bon Scott");
ans3.add("Malcolm Young");
ans3.add("Angus Young");
Question q3 = new Question("Who was AC/DC's original lead singer?", ans3, "Bon Scott");
FileOutputStream fos = null; //create an output stream to write the objects to a file
ObjectOutputStream out = null;
try
{
fos = new FileOutputStream("RockQuestions"); //RockQuestions can be any file name, I didn't include an extension but you could make it whatever you want
out = new ObjectOutputStream(fos);
out.writeObject(q1);
out.writeObject(q2);
out.writeObject(q3);
out.close();
}
catch(IOException ex)
{
ex.printStackTrace();
}FileInputStream fis = null;
ObjectInputStream in = null;
try
{
fis = new FileInputStream("RockQuestions");
in = new ObjectInputStream(fis);
while (true){ //I couldn't find/remember how to check eof with the object reader so I'm relying on the eof exception being thrown to break out of here...
questions.add((Question) in.readObject()); //need to cast the read object to the correct type
}
}
catch(EOFException e){
System.out.println("Reached EOF"); //this occurs when the entire file has been read
}
catch(IOException ex)
{
ex.printStackTrace();
}
catch(ClassNotFoundException ex)
{
ex.printStackTrace();
}
finally {
if (in != null){
try {
in.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (fis != null){
try {
fis.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
public class shape {
//methods and class member variables here.
}public class circle extends shape {
//methods and class member variables here.
}import java.util.*;
class Line extends Shape {
private Point start, end;
private double width;
protected String name;
Line(String name, Point x, Point y, double w)
{
this.name = name;
start = x;
end = y;
width = w;
}
public String toString() {
return name + " starts at " + start + " to " + end + " of width = " + width;
}
}
class fancyLine extends Line{
private String drawType;
fancyLine(String n, Point a, Point b, double w, String type)
{
super(n,a,b,w);
drawType = type;
}
public String toString()
{
return super.toString() + " and is a " + drawType;
}
}
class Point extends Shape{ //possibly extends line
public int x, y, z;
Point(int x, int y) {
this.x = x;
this.y = y;
}
Point(Point p) {
this(p.x, p.y);
}
Point(int x, int y, int z){
this.x = x;
this.y = y;
this.z = z;
}
public String toString()
{
return "(" + x + "," + y +")";
}
}
class Circle extends Shape{ //possibly extend line
protected double radius;
protected double center;
protected double name;
protected double area;
Circle(String name, Point p, double r) {
center = p;
radius = r;
area = (3.14 * (radius * radius));
this.name = name;
}
Circle(String n, Circle x) {
this.center = center;
this.radius = radius;
area = (3.14 * (radius * radius));
n = name;
}
public double getArea()
{
return Math.PI * Math.pow(radius, 2);
}
public String toString()
{
return name + " originates at " + center + " extends for a radius of " + radius + "the original circles has an area of " + area;
}
}
class Cylinder extends Circle{
private int height;
private Point cylCenter;
private double cylRadius;
Cylinder(String n, Point x, double r, int h){
super(n, x, r);
height = h;
cylCenter = x;
cylRadius = r;
name = n;
}
Cylinder(String n, Circle x, int h){
super(n, x, r);
height = h;
cylCenter = x;
cylRadius = r;
name = n;
}
public String toString()
{
return name + " originates at " + cylCenter + " with a radius of " + cylRadius + " with a height of " + height;
}
}
class Rectangle extends Shape {
protected Point one, two, three, four;
protected int height;
protected String name;
Rectangle(String n, Point start, Point width, Point top){
name = n;
one = start;
two = width;
three = top;
height = getValy(three) - getValy(one);
}
int getValx (Point x) {
return x.x;
}
int getValy (Point y) {
return y.y;
}
public String toString()
{
return name + " originates at " + one + " its second point is " + two + " and has a height of " + height;
}
}
class Cube extends Rectangle {
private int depth;
Cube(String n, Point start, Point width, Point top, int depth) {
super(n, start, width, top);
this.depth = depth;
}
}
abstract class Shape {
static ArrayList<Shape> container = new ArrayList<Shape>();
public static void main(String args[]) {
//define the points
Point origin = new Point (0,0);
Point twoTwo = new Point (2,2);
Point twoZero = new Point (2,0);
Point fourFour = new Point (4,4);
Point fiveFive = new Point (5,5);
Point sixSix = new Point (6,6);
Point eightEight = new Point (8,8);
Point zeroZeroFive = new Point (0,0,5);
Line lineOne = new Line("Line One", origin, twoTwo, 2.1);
container.add(lineOne); //line
Line lineTwo = new fancyLine("Line Two", origin, twoTwo, 2.1, "Fancy");
container.add(lineTwo); //fancy line
Circle circleOne = new Circle("Circle One", twoTwo, 3.1);
container.add(circleOne); //circle
Cylinder cylOne = new Cylinder("Cylinder One", circleOne, 5);
container.add(cylOne); //cylinder
Cylinder cylTwo = new Cylinder("Cylinder Two", twoTwo, 3.1, 5);
container.add(cylTwo); //cylinder method two
Rectangle recOne = new Rectangle("Rectangle One", origin, twoZero, twoTwo);
container.add(recOne); //rectangle
Cube cubeOne = new Cube("Cube One", origin, twoZero, twoTwo, 2);
container.add(cubeOne); //cube
for (Shape a : container)
System.out.println(a + " ");
}
}
Thanks for the help, I'm back with some more personal problems haha
We have a take home final and I don't understand what the following questions mean, I think some of it is the way he words it and the other part is my lack of knowledge of java in general. Here are the questions, hopefully you can help
1.
Show, by way of example and descriptions, how inheritance works to allow “specializing” an existing class to extend method behavior by “piggybacking” on existing code, rather than having to copy and paste it into the new class.
2.
Show, by way of example and descriptions, how composition works in Java to allow a “subobject” to be stored as an instance variable inside another object. Also, show in your example how the subobject’s data are accessed. Write getter and setter methods for your class.
import java.util.ArrayList;
public class Speaker
{ //instance variable
protected String name;
public String toString()
{
return name + " beats";
}
public static void main(String[] s)
{ //creates the types of speakers
Component alpine = new Sub("Alpine");
//add those speakers to a container
ArrayList<Speaker> speakers = new ArrayList<Speaker>();
speakers.add(alpine);
//print the above speakers to the console
for (Speaker a : speakers)
System.out,print(a + " ");
}
}
abstract class Component extends Speaker
class Sub extends Component
{
Sub(String s)
{ name = s;
}
//print representation
public String toString()
{
return name + " makes a bass noise";
}
}class Fruit {
private in age = 0;
private String ripeness = ripe;
public void setRipeness(String ripeness){
this.ripeness = ripeness;}
public void getAge() {
return age}
}
class Apple {
private Fruit b = new Fruit(fruit);
}// numbers is a Character[] ArrayList
public void fillLetters() {
Character[] n2 = {'a', 'b', 'c'};
numbers.add(n2);
Character[] n3 = {'d', 'e', 'f'};
numbers.add(n3);
Character[] n4 = {'g', 'h', 'i'};
numbers.add(n4);
Character[] n5 = {'j', 'k', 'l'};
numbers.add(n5);
Character[] n6 = {'m', 'n', 'o'};
numbers.add(n6);
Character[] n7 = {'p', 'r', 's'};
numbers.add(n7);
Character[] n8 = {'t', 'u', 'v'};
numbers.add(n8);
Character[] n9 = {'w', 'x', 'y'};
numbers.add(n9);
}
public void writeToFile(int[] nums) {
int number = 0, letter = 0;
// This is just a place holder. I imagine this format will work
// If I can find a way to properly increment through each number and letter
while (true) {
for (int i = 0; i < nums.length; i++) {
pStream.print((char) (numbers.get(i - 2)[letter] - 32));
System.out.print((char) (numbers.get(i - 2)[letter] - 32));
}
pStream.println();
System.out.println();
}
}
import java.util.*;
public class Permutation {
public ArrayList<String> getPerms(String s) {
ArrayList<String> list = new ArrayList<String>();
if (s.length() == 1)
list.add(s);
else {
for (int i = 0; i < s.length(); i++) {
char x = s.charAt(i);
String y = "";
for (int j = 0; j < s.length(); j++) {
if (i != j)
y += s.charAt(j);
}
ArrayList<String> results = getPerms(y);
for (String sf : results) {
list.add(x + sf);
}
}
}
return list;
}
public static void main(String[] ar) {
for (String s : new Permutation().getPerms("abcdefg")) {
System.out.println(s);
}
}
}