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HarryDulaneyHarryDulaney
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Chapter 11 complete
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‎src/ch_11/Exercise11_11.java

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package ch_11;
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import java.util.ArrayList;
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import java.util.Scanner;
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/**
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* 11.11 (Sort ArrayList) Write the following method that sorts an ArrayList of
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* numbers:
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* public static void sort(ArrayList<Integer> list)
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* <p>
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* Write a test program that prompts the user to enter 5 numbers, stores them in an
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* array list, and displays them in increasing order.
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*/
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public class Exercise11_11 {
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public static void main(String[] args) {
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Scanner in = new Scanner(System.in);
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System.out.print("Enter five integers: ");
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ArrayList<Integer> list = new ArrayList<>();
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for (int i = 0; i < 5; i++) {
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list.add(in.nextInt());
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}
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sort(list);
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System.out.print("The numbers in increasing order: ");
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System.out.print("\n" + list.toString());
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in.close();
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}
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public static void sort(ArrayList<Integer> list) {
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boolean loop = true;
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while (loop) {
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loop = false; //Reset to check if can remain false
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for (int n = 0; n < list.size(); n++) {
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for (int i = n; i < list.size(); i++) {
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if (!(i == n)) {
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if (list.get(n) > list.get(i)) {
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loop = true; // Not finished sorting..
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swapElements(list, n, i);
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}
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}
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}
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}
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}
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}
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static void swapElements(ArrayList<Integer> list, int idx1, int idx2) {
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Integer temp = list.get(idx1);
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list.set(idx1, list.get(idx2));
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list.set(idx2, temp);
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}
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}

‎src/ch_11/Exercise11_12.java

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package ch_11;
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import java.util.ArrayList;
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import java.util.ListIterator;
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import java.util.Scanner;
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/**
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* 11.12 (Sum ArrayList) Write the following method that returns the sum of all numbers in an ArrayList:
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* public static double sum(ArrayList<Double> list)
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* <p>
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* Write a test program that prompts the user to enter 5 numbers, stores them in an
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* array list, and displays their sum.
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*/
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public class Exercise11_12 {
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public static void main(String[] args) {
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ArrayList<Double> list = new ArrayList<>();
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Scanner in = new Scanner(System.in);
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System.out.print("Enter 5 numbers: ");
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for (int i = 0; i < 5; i++) {
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list.add(in.nextDouble());
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}
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System.out.println("Sum = " + sum(list));
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in.close();
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}
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public static double sum(ArrayList<Double> list) {
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double sum = 0;
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ListIterator<Double> iterator = list.listIterator();
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while (iterator.hasNext()) {
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sum += iterator.next();
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}
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return sum;
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}
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}

‎src/ch_11/Exercise11_13.java

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System.out.print("The distinct integers are ");
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for (Integer integer : testList) {
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System.out.print(integer + " ");
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}
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input.close();

‎src/ch_11/Exercise11_14.java

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package ch_11;
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import java.util.ArrayList;
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import java.util.Collections;
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import java.util.Scanner;
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/**
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* 11.14 (Combine two lists) Write a method that returns the union of two array lists of
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* integers using the following header:
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* public static ArrayList<Integer> union(ArrayList<Integer> list1, ArrayList<Integer> list2)
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* <p>
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* For example, the union of two array lists {2, 3, 1, 5} and {3, 4, 6} is
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* {2, 3, 1, 5, 3, 4, 6}.
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* <p>
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* Write a test program that prompts the user to enter two lists,
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* each with five integers, and displays their union. The numbers are separated by
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* exactly one space in the output. Here is a sample run:
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* Enter five integers for list1: 3 5 45 4 3
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* Enter five integers for list2: 33 51 5 4 13
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* The combined list is 3 5 45 4 3 33 51 5 4 13
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*/
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public class Exercise11_14 {
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public static void main(String[] args) {
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Scanner in = new Scanner(System.in);
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ArrayList<Integer> one = new ArrayList<>();
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ArrayList<Integer> two = new ArrayList<>();
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System.out.print("Enter 5 integers for list1: ");
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for (int i = 0; i < 5; i++) {
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one.add(in.nextInt());
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}
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System.out.print("Enter 5 integers for list2: ");
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for (int i = 0; i < 5; i++) {
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two.add(in.nextInt());
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}
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System.out.println("The combined list is " + union(one, two).toString());
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in.close();
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}
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public static ArrayList<Integer> union(ArrayList<Integer> list1, ArrayList<Integer> list2) {
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list1.addAll(list2);
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return list1;
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}
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}

‎src/ch_11/Exercise11_15.java

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package ch_11;
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import java.util.ArrayList;
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import java.util.Scanner;
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/**
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* 11.15 (Area of a convex polygon) A polygon is convex if it contains any line segments
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* that connects two points of the polygon.
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* <p>
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* Write a program that prompts the user to enter the number of points in a convex polygon, then enter the points
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* clockwise,
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* and display the area of the polygon.
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* <p>
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* Here is a sample run of the program:
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* Enter the number of the points: 7
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* Enter the coordinates of the points:
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* -12 0 -8.5 10 0 11.4 5.5 7.8 6 -5.5 0 -7 -3.5 -3.5
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* The total area is 250.075
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*/
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public class Exercise11_15 {
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public static void main(String[] args) {
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Scanner in = new Scanner(System.in);
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System.out.print("Enter the number of points: ");
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int numPoints = in.nextInt();
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ArrayList<double[]> pts = new ArrayList<>();
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System.out.print("Enter the coordinates of the points in the convex polygon: ");
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for (int i = 0; i < numPoints; i++) {
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double[] pt = new double[2];
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for (int xy = 0; xy < 2; xy++) {
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pt[xy] = in.nextDouble();
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}
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pts.add(pt);
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}
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System.out.print("The area of the convex polygon is ");
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System.out.println(getAreaConvexPolygon(pts) + "");
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in.close();
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}
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static double getAreaConvexPolygon(ArrayList<double[]> pts) {
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double[] lastPoint = pts.get(pts.size() - 1);
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double[] firstPoint = pts.get(0);
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double operand1 = lastPoint[0] * firstPoint[1]; // xn * y1
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for (int i = 0; i < pts.size() - 1; i++) {
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double[] pt = pts.get(i);
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double[] nextPt = pts.get(i + 1);
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operand1 += pt[0] * nextPt[1]; // x1 * y2 + x2 * y3 + x(n) * y(n+1) + {x(n) * y1}
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}
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double operand2 = lastPoint[1] * firstPoint[0]; // yn * x1
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for (int i = 0; i < pts.size() - 1; i++) {
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double[] pt = pts.get(i);
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double[] nextPt = pts.get(i + 1);
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operand2 += pt[1] * nextPt[0]; // y1 * x2 + y2 * x3 + y(n) + x(n+1) + {y(n) * x1}
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}
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return Math.abs((operand1 - operand2) * 0.5);
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}
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}

‎src/ch_11/Exercise11_16.java

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package ch_11;
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import java.util.ArrayList;
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import java.util.Scanner;
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/**
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* *11.16 (Addition quiz) Rewrite Listing 5.1 RepeatAdditionQuiz.java to alert the user
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* if an answer is entered again. Hint: use an array list to store answers. Here is a
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* sample run:
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* What is 5 + 9? 12
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* Wrong answer. Try again. What is 5 + 9? 34
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* Wrong answer. Try again. What is 5 + 9? 12
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* You already entered 12
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* Wrong answer. Try again. What is 5 + 9? 14
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* You got it!
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*/
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public class Exercise11_16 {
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public static void main(String[] args) {
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ArrayList<Integer> guesses = new ArrayList<>();
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Scanner input = new Scanner(System.in);
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int number1 = (int) (Math.random() * 10);
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int number2 = (int) (Math.random() * 10);
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System.out.print("What is " + number1 + " + " + number2 + "? ");
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int answer = input.nextInt();
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while (answer != number1 + number2) {
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if (guesses.contains(answer)) {
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System.out.println("You've already entered " + answer);
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System.out.print("Try again. What is " + number1 + " + " + number2 + "? ");
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answer = input.nextInt();
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} else {
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guesses.add(answer);
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System.out.print("Wrong answer. Try again. What is " + number1 + " + " + number2 + "? ");
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answer = input.nextInt();
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}
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}
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input.close();
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System.out.println("You got it!");
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}
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}

‎src/ch_11/Exercise11_17.java

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package ch_11;
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import java.util.ArrayList;
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import java.util.Scanner;
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/**
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* *11.17 (Algebra: perfect square) Write a program that prompts
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* the user to enter an integer m and find the smallest integer n such that m * n is a perfect square. (Hint:
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* Store all smallest factors of m into an array list. n is the product of the factors that
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* appear an odd number of times in the array list.
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* <p>
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* For example, consider m = 90, store the factors 2, 3, 3, 5 in an array list. 2 and 5 appear an odd number of times
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* in the array list. So, n is 10.)
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* <p>
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* Here are sample runs:
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* Enter an integer m: 1500
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* The smallest number n for m * n to be a perfect square is 15
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* m * n is 22500
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* <p>
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* <p>
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* Enter an integer m: 63
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* The smallest number n for m * n to be a perfect square is 7
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* m * n is 441
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*/
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public class Exercise11_17 {
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public static void main(String[] args) {
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Scanner in = new Scanner(System.in);
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System.out.print("Enter an integer: ");
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int m = in.nextInt();
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int n = findN(findSmallestFactors(m));
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System.out.println("The smallest number n for m * n to be a perfect square is " + n);
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System.out.println("m * n is " + m * n);
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}
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static ArrayList<Integer> findSmallestFactors(int m) {
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ArrayList<Integer> smallFactors = new ArrayList<>();
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for (int f = 2; m != 1; f++) {
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if (m % f == 0) {
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smallFactors.add(f);
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m /= f;
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f = 1; // Reset the test factor
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}
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}
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return smallFactors;
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}
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static Integer findN(ArrayList<Integer> factors) {
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ArrayList<Integer> oddCounts = new ArrayList<>();
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for (int i = 0; i < factors.size(); i++) {
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int num = factors.get(i);
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int count = 0;
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for (Integer integer : factors) {
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if (integer == num) {
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count++;
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}
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}
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if (count % 2 != 0 && !oddCounts.contains(num)) {
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oddCounts.add(num);
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}
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}
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Integer result = 1;
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for (Integer oddCount : oddCounts) {
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result *= oddCount;
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}
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return result;
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}
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}

‎src/ch_11/area_convex_polygon.gif

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‎src/ch_11/exercise11_02/Exercise11_02.java

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Person person = new Person();
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person.setName("Garry Barryman");
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Student student = new Student(Student.SENIOR);
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student.setName("Jingle Jam");
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student.setName("Jingle PB&J");
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Employee employee = new Employee("Delray Beach,FL", 45_750.00, new MyDate());
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employee.setName("Sarah Stodenbyer");
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Faculty faculty = new Faculty(new double[]{9.0, 5.0}, 5);

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