Example 11

Chapter 11

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Introduction to Java Programming, Tenth Edition, Y. Daniel Liang

public class SimpleGeometricObject {
  private String color = "white";
  private boolean filled;
  private java.util.Date dateCreated;
 
  /** Construct a default geometric object */
  public SimpleGeometricObject() {
    dateCreated = new java.util.Date();
  }

  /** Construct a geometric object with the specified color
    *  and filled value */
  public SimpleGeometricObject(String color, boolean filled) {
    dateCreated = new java.util.Date();
    this.color = color;
    this.filled = filled;
  }

  /** Return color */
  public String getColor() {
    return color;
  }

  /** Set a new color */
  public void setColor(String color) {
    this.color = color;
  }

  /** Return filled. Since filled is boolean,
     its get method is named isFilled */
  public boolean isFilled() {
    return filled;
  }

  /** Set a new filled */
  public void setFilled(boolean filled) {
    this.filled = filled;
  }
 
  /** Get dateCreated */
  public java.util.Date getDateCreated() {
    return dateCreated;
  }
 
  /** Return a string representation of this object */
  public String toString() {
    return "created on " + dateCreated + "\ncolor: " + color +
      " and filled: " + filled;
  }
}

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Introduction to Java Programming, Tenth Edition, Y. Daniel Liang

public class CircleFromSimpleGeometricObject
    extends SimpleGeometricObject {
  private double radius;

  public CircleFromSimpleGeometricObject() {
  }

  public CircleFromSimpleGeometricObject(double radius) {
    this.radius = radius;
  }

  public CircleFromSimpleGeometricObject(double radius,
      String color, boolean filled) {
    this.radius = radius;
    setColor(color);
    setFilled(filled);
  }

  /** Return radius */
  public double getRadius() {
    return radius;
  }

  /** Set a new radius */
  public void setRadius(double radius) {
    this.radius = radius;
  }

  /** Return area */
  public double getArea() {
    return radius * radius * Math.PI;
  }
 
  /** Return diameter */
  public double getDiameter() {
    return 2 * radius;
  }
 
  /** Return perimeter */
  public double getPerimeter() {
    return 2 * radius * Math.PI;
  }

  /* Print the circle info */
  public void printCircle() {
    System.out.println("The circle is created " + getDateCreated() +
      " and the radius is " + radius);
  }
}

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Introduction to Java Programming, Tenth Edition, Y. Daniel Liang

public class RectangleFromSimpleGeometricObject
    extends SimpleGeometricObject {
  private double width;
  private double height;

  public RectangleFromSimpleGeometricObject() {
  }

  public RectangleFromSimpleGeometricObject(
      double width, double height) {
    this.width = width;
    this.height = height;
  }

  public RectangleFromSimpleGeometricObject(
      double width, double height, String color, boolean filled) {
    this.width = width;
    this.height = height;
    setColor(color);
    setFilled(filled);
  }

  /** Return width */
  public double getWidth() {
    return width;
  }

  /** Set a new width */
  public void setWidth(double width) {
    this.width = width;
  }

  /** Return height */
  public double getHeight() {
    return height;
  }

  /** Set a new height */
  public void setHeight(double height) {
    this.height = height;
  }

  /** Return area */
  public double getArea() {
    return width * height;
  }

  /** Return perimeter */
  public double getPerimeter() {
    return 2 * (width + height);
  }
}

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Introduction to Java Programming, Tenth Edition, Y. Daniel Liang

public class TestCircleRectangle {
  public static void main(String[] args) {
    CircleFromSimpleGeometricObject circle =
      new CircleFromSimpleGeometricObject(1);
    System.out.println("A circle " + circle.toString());
    System.out.println("The color is " + circle.getColor());
    System.out.println("The radius is " + circle.getRadius());
    System.out.println("The area is " + circle.getArea());
    System.out.println("The diameter is " + circle.getDiameter());
   
    RectangleFromSimpleGeometricObject rectangle =
      new RectangleFromSimpleGeometricObject(2, 4);
    System.out.println("\nA rectangle " + rectangle.toString());
    System.out.println("The area is " + rectangle.getArea());
    System.out.println("The perimeter is " +
      rectangle.getPerimeter());
  }
}

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Introduction to Java Programming, Tenth Edition, Y. Daniel Liang

public class PolymorphismDemo {
  /** Main method */
  public static void main(String[] args) {
    // Display circle and rectangle properties
    displayObject(new CircleFromSimpleGeometricObject
        (1, "red", false));
    displayObject(new RectangleFromSimpleGeometricObject
        (1, 1, "black", true));
  }

  /** Display geometric object properties */
  public static void displayObject(SimpleGeometricObject object) {
    System.out.println("Created on " + object.getDateCreated() +
      ". Color is " + object.getColor());
  }
}

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Introduction to Java Programming, Tenth Edition, Y. Daniel Liang

public class DynamicBindingDemo {
  public static void main(String[] args) {
    m(new GraduateStudent());
    m(new Student());
    m(new Person());
    m(new Object());
  }

  public static void m(Object x) {
    System.out.println(x.toString());
  }
}

class GraduateStudent extends Student {
}

class Student extends Person {
  @Override
  public String toString() {
    return "Student";
  }
}

class Person extends Object {
  @Override
  public String toString() {
    return "Person";
  }
}

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Introduction to Java Programming, Tenth Edition, Y. Daniel Liang

public class CastingDemo {
  /** Main method */
  public static void main(String[] args) {
    // Create and initialize two objects
    Object object1 = new CircleFromSimpleGeometricObject(1);
    Object object2 = new RectangleFromSimpleGeometricObject(1, 1);

    // Display circle and rectangle
    displayObject(object1);
    displayObject(object2);
  }

  /** A method for displaying an object */
  public static void displayObject(Object object) {
    if (object instanceof CircleFromSimpleGeometricObject) {
      System.out.println("The circle area is " +
        ((CircleFromSimpleGeometricObject)object).getArea());
      System.out.println("The circle diameter is " +
        ((CircleFromSimpleGeometricObject)object).getDiameter());
    }
    else if (object instanceof
                  RectangleFromSimpleGeometricObject) {
      System.out.println("The rectangle area is " +
        ((RectangleFromSimpleGeometricObject)object).getArea());
    }
  }
}

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Introduction to Java Programming, Tenth Edition, Y. Daniel Liang

import java.util.ArrayList;

public class TestArrayList {
  public static void main(String[] args) {
    // Create a list to store cities
    ArrayList<String> cityList = new ArrayList<>();

    // Add some cities in the list
    cityList.add("London");
    // cityList now contains [London]
    cityList.add("Denver");
    // cityList now contains [London, Denver]
    cityList.add("Paris");
    // cityList now contains [London, Denver, Paris]
    cityList.add("Miami");
    // cityList now contains [London, Denver, Paris, Miami]
    cityList.add("Seoul");
    // contains [London, Denver, Paris, Miami, Seoul]
    cityList.add("Tokyo");
    // contains [London, Denver, Paris, Miami, Seoul, Tokyo]

    System.out.println("List size? " + cityList.size());
    System.out.println("Is Miami in the list? " +
      cityList.contains("Miami"));
    System.out.println("The location of Denver in the list? "
      + cityList.indexOf("Denver"));
    System.out.println("Is the list empty? " +
      cityList.isEmpty()); // Print false

    // Insert a new city at index 2
    cityList.add(2, "Xian");
    // contains [London, Denver, Xian, Paris, Miami, Seoul, Tokyo]

    // Remove a city from the list
    cityList.remove("Miami");
    // contains [London, Denver, Xian, Paris, Seoul, Tokyo]

    // Remove a city at index 1
    cityList.remove(1);
    // contains [London, Xian, Paris, Seoul, Tokyo]

    // Display the contents in the list
    System.out.println(cityList.toString());

    // Display the contents in the list in reverse order
    for (int i = cityList.size() - 1; i >= 0; i--)
      System.out.print(cityList.get(i) + " ");
    System.out.println();
   
    // Create a list to store two circles
    java.util.ArrayList<CircleFromSimpleGeometricObject> list
      = new java.util.ArrayList<>();
   
    // Add two circles
    list.add(new CircleFromSimpleGeometricObject(2));
    list.add(new CircleFromSimpleGeometricObject(3));
   
    // Display the area of the first circle in the list
    System.out.println("The area of the circle? " +
      list.get(0).getArea());
  }
}

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Introduction to Java Programming, Tenth Edition, Y. Daniel Liang

import java.util.ArrayList;
import java.util.Scanner;

public class DistinctNumbers {
  public static void main(String[] args) {
    ArrayList<Integer> list = new ArrayList<>();
   
    Scanner input = new Scanner(System.in);  
    System.out.print("Enter integers (input ends with 0): ");
    int value;
   
    do {
      value = input.nextInt(); // Read a value from the input
     
      if (!list.contains(value) && value != 0)
        list.add(value); // Add the value if it is not in the list
    } while (value != 0);

    // Display the distinct numbers
    for (int i = 0; i < list.size(); i++)
      System.out.print(list.get(i) + " ");
  }
}

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Introduction to Java Programming, Tenth Edition, Y. Daniel Liang

import java.util.ArrayList;

public class MyStack {
  private ArrayList<Object> list = new ArrayList<>();

  public boolean isEmpty() {
    return list.isEmpty();
  }

  public int getSize() {
    return list.size();
  }

  public Object peek() {
    return list.get(getSize() - 1);
  }

  public Object pop() {
    Object o = list.get(getSize() - 1);
    list.remove(getSize() - 1);
    return o;
  }

  public void push(Object o) {
    list.add(o);
  }

  @Override /** Override the toString in the Object class */
  public String toString() {
    return "stack: " + list.toString();
  }
}

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