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Commit 07dea4d

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Merge pull request HarryDulaney#37 from HarryDulaney/New_Chapters_New_Solutions
Added 22_08 Exercise Solution + 22 09 and 22 10 Exercise Questions
2 parents dc0debe + e05629f commit 07dea4d

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9 files changed

+288
-54
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9 files changed

+288
-54
lines changed

‎ch_13/exercise13_01/Triangle.java‎

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//__________________________UML DIAGRAM_____________________________*
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/* |
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* /GeometricObject/ |
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*-------------------------------------------------------------------|
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*------------------------------------------------------------------|
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* -color: String |
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* -filled: boolean |
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* -dateCreated : java.util.Date |
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* -dateCreated : java.util.Date |
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* |
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*-------------------------------------------------------------------|
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*------------------------------------------------------------------|
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* #GeometricObject() |
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* #GeometricObject(color:String,filled:boolean) |
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* |
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* +isFilled(): boolean |
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* +setFilled(filled: boolean): void |
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* +getDateCreated(): java.util.Date |
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* |
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* +toString(): String |
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* |
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* +toString(): String |
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* /+getArea()/: double/ |
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* /+getPerimeter(): double/ |
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* __________________________________________________________________| */
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* _________________________________________________________________| */
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/* ^
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^
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^
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* -side3: double |
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* _________________________________________________________________|
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* |
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* +Triangle2D() |
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* +Triangle2D(side1:double,side2:double,side3:double) |
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* +Triangle2D() |
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* +Triangle2D(side1:double,side2:double,side3:double) |
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* +getSide1(): double |
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* +setSide1(side1: double): void |
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* +getSide2(): double |

‎ch_22/Exercise22_09.java‎

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package ch_22;
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/**
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* **22.9 (Geometry: gift-wrapping algorithm for finding a convex hull) Section 22.10.1
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* introduced the gift-wrapping algorithm for finding a convex hull for a set of
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* points. Assume that the Java’s coordinate system is used for the points. Implement the algorithm using the following method:
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* // Return the points that form a convex hull
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* public static ArrayList<Point2D> getConvexHull(double[][]s)
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* Point2D is defined in Section 9.6.
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* Write a test program that prompts the user to enter the set size and the points
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* and displays the points that form a convex hull.Here is a sample run:
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*/
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public class Exercise22_09 {
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}

‎ch_22/Exercise22_10.java‎

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package ch_22;
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/**
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* 22.10 (Number of prime numbers) Programming Exercise 22.8 stores the prime numbers in a file named PrimeNumbers.dat.
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* Write a program that finds the number of prime numbers that are less than or equal to 10, 100, 1,000, 10,000,
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* 100,000, 1,000,000, 10,000,000, 100,000,000, 1,000,000,000, and
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* 10,000,000,000. Your program should read the data from PrimeNumbers.dat
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*/
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public class Exercise22_10 {
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}
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package ch_22.exercise22_08;
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import java.io.*;
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/**
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* *22.8 (All prime numbers up to 10,000,000,000) Write a program that finds
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* all prime numbers up to 10,000,000,000. There are approximately
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* 455,052,511 such prime numbers. Your program should meet the following
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* requirements:
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* ■しかく Your program should store the prime numbers in a binary data file, named
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* PrimeNumbers.dat. When a new prime number is found, the number is
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* appended to the file.
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* ■しかく To find whether a new number is prime, your program should load the
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* prime numbers from the file to an array of the long type of size 10000.
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* If no number in the array is a divisor for the new number, continue to read
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* the next 10000 prime numbers from the data file, until a divisor is found
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* or all numbers in the file are read. If no divisor is found, the new number
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* is prime.
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* ■しかく Since this program takes a long time to finish, you should run it as a batch
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* job from a UNIX machine. If the machine is shut down and rebooted, your
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* program should resume by using the prime numbers stored in the binary data
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* file rather than start over from scratch.
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*/
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public class Exercise22_08 {
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private static PrimeStorage primeStorage;
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private static final String[] packageParts = Exercise22_08.class.getPackage().getName().split("\\.");
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private static final String PATH = packageParts[0] + File.separator + packageParts[1] + File.separator + "PrimeNumbers.dat";
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private static long[] primeReadBuffer = new long[10000];
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private static final long UPPER_BOUND = 10_000_000_000L;
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private static boolean reachedEndOfBuffer = false;
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public static void main(String[] args) {
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try {
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primeStorage = new PrimeStorage(PATH);
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long checkNum = primeStorage.getNextNumberToCheck();
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// Check primes until reaching upper bound
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while (checkNum < UPPER_BOUND) {
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boolean isPrime = checkPrime(checkNum, primeStorage);
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if (isPrime) {
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primeStorage.appendPrime(checkNum);
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}
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checkNum++;
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}
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} catch (Exception e) {
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System.err.println("Could not create and/or read/write file needed to store prime numbers on this device. " +
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"Please confirm Security Manager will allow create/read/write file storage.");
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System.exit(0);
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}
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}
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private static boolean checkPrime(long checkNum, PrimeStorage primeStorage) throws IOException {
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boolean loop = true;
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boolean isPrime = true;
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primeStorage.setPosition(0);
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while (loop) {
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primeReadBuffer = primeStorage.readNextPrimes();
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boolean isDivisible = isDivisible(primeReadBuffer, checkNum);
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if (isDivisible) {
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// checkNum is not prime
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loop = false;
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isPrime = false;
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break;
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} else if (reachedEndOfBuffer) {
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loop = false;
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break;
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}
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}
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return isPrime;
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}
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public static boolean isDivisible(long[] primes, long checkNum) {
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for (long prime : primes) {
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if (prime == 0) {
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reachedEndOfBuffer = true;
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return false;
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}
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if (checkNum % prime == 0) {
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return true;
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}
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}
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return false;
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}
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}

‎ch_22/exercise22_08/PrimeNumbers.dat‎

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package ch_22.exercise22_08;
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import java.io.EOFException;
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import java.io.File;
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import java.io.IOException;
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import java.io.RandomAccessFile;
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public class PrimeStorage {
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protected File dataFile;
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private boolean firstRun;
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private long nextNumberToCheck = 0;
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private RandomAccessFile randomAccessFile;
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public PrimeStorage(String storageFilePath) throws Exception {
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dataFile = new File(storageFilePath);
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boolean createdOrExists = dataFile.exists();
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/* If file does not exist, this is the first run, starting from first prime number */
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if (!createdOrExists) {
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this.firstRun = true;
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try {
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createdOrExists = dataFile.createNewFile();
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} catch (IOException ioe) {
24+
throw new Exception("Error while trying to create storage file: " + ioe.getLocalizedMessage());
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}
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}
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if (createdOrExists) {
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/* Need file channel to be: Closable, seekable, readable, writable */
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try {
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randomAccessFile = new RandomAccessFile(dataFile, "rws");
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// Handle different startup flows
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if (firstRun) {
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nextNumberToCheck = initializePrimes();
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} else {
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nextNumberToCheck = restartPrimes();
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}
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} catch (IOException ioException) {
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throw new Exception("IOException while creating in and out file stream: \n" + ioException.getMessage());
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}
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}
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}
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private long restartPrimes() throws IOException {
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long totalBytes = randomAccessFile.length();
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randomAccessFile.seek(totalBytes - 8); // Seek to read the last 8 bytes in the file
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long lastPrime = randomAccessFile.readLong();
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return nextNumberToCheck = lastPrime + 1;
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}
51+
52+
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private long initializePrimes() throws IOException {
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/* First time running program, prep the file by writing first two prime numbers */
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randomAccessFile.writeLong(2L);
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randomAccessFile.writeLong(3L);
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return 4;
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}
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public long[] readNextPrimes() {
61+
long[] primes = new long[10000];
62+
try {
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for (int i = 0; i < primes.length && (randomAccessFile.getFilePointer() < randomAccessFile.length()); i++) {
64+
primes[i] = randomAccessFile.readLong();
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}
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} catch (EOFException eof) {
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System.out.println("End of File Reached");
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return primes;
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} catch (IOException e) {
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e.printStackTrace();
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}
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return primes;
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}
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public void appendPrime(long primeNumber) throws IOException {
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long totalBytes = randomAccessFile.length();
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randomAccessFile.seek(totalBytes);
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randomAccessFile.writeLong(primeNumber);
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}
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public boolean isFirstRun() {
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return firstRun;
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}
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public long getNextNumberToCheck() {
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return nextNumberToCheck;
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}
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public void setNextNumberToCheck(long nextNumberToCheck) {
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this.nextNumberToCheck = nextNumberToCheck;
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}
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public void setPosition(long position) throws IOException {
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randomAccessFile.seek(position);
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}
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}

‎ch_22/exercise22_08/Test.java‎

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package ch_22.exercise22_08;
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import java.io.EOFException;
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import java.io.File;
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import java.io.IOException;
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import java.io.RandomAccessFile;
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/**
9+
* Integration Test will print out the prime numbers from PrimeNumbers.dat
10+
*/
11+
public class Test {
12+
private static final String[] packageParts = Exercise22_08.class.getPackage().getName().split("\\.");
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private static final String PATH = packageParts[0] + File.separator + packageParts[1] + File.separator + "PrimeNumbers.dat";
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public static void main(String[] args) {
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try {
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RandomAccessFile randomAccessFile = new RandomAccessFile(new File(PATH), "rw");
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while (true) {
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long nextLong = randomAccessFile.readLong();
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System.out.println("Next long: " + nextLong);
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}
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} catch (EOFException eof) {
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System.out.println("EOF reached");
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} catch (IOException ioException) {
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System.out.println("IOException while creating in and out file stream: \n" + ioException.getMessage());
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}
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}
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}

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