if (i % 2 == 0) { return 4 + method(i + 5) } if (i % 2 == 1) { return 2 + method(i + 3) } public static int method( int i )

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1 Review Exercises Here is a list of review exercises. There are times when an exercise will be open ended, allowing you to pursue multiple aspects of the material. While encompassing some areas we have studied, you should further supplement your studying by reviewing: your notes, your project assignments, exercise questions given in lecture, exercise questions given in discussion sessions, and problems from the chapters in our textbook. 1. Fill in the missing pieces/syntax of the method utilized below. State the base case(s), recursive case(s), and recursive step(s) utilized in the method. Also, discuss how the program is moving from the start to the base case(s). Finally, step through the code, showing the process of its execution. method( ) if (i > 21) { return 1 if (i % 2 == 0) { return 4 + method(i + 5) if (i % 2 == 1) { return 2 + method(i + 3) First, here are the blanks filled in: public static int method( int i ) (Note: the static modifier is necessary when method is used directly by the main method, static is left off when not used directly by main, when not used in a static context. You should test the method in both situations to see that it operates the same, but the need for static changes.) if (i > 21) // Base Case (BC) return 1 if (i % 2 == 0) // Recursive Case #1 (RC1) return 4 + method(i + 5) // Recursive Step #1 (RS1) if (i % 2 == 1) // Recursive Case #2 (RC2) return 2 + method(i + 3) // Recursive Step #2 (RS2) Sample execution if the input parameter initially given to method is 0. Note how the indentation lines up, connecting the statement where the recursive call begins to the finalization of the return statement, where the all the details of the entire return are known. Also, note how the value of i is expressed and lines up within and still connected to its usage within each recursive call. method(0) i = 0 // RC1 is called

2 return (4 + method(5)) i = 5 // RC2 is called return (2 + method(8)) i = 8 // RC1 is called return (4 + method(13)) i = 13 // RC2 is called return (2 + method(16)) i = 16 // RC1 is called return (4 + method(21)) i = 21 // RC2 is called return (2 + method(24)) i = 24 // BC is reached return 1 return 2+1 = 3 => completes the statement: return (2 + method(26)) return = 7 => completes the statement: return (4 + method(21)) return 2+7 = 9 => completes the statement: return (2 + method(16)) return 4+9 = 13 => completes the statement: return (4 + method(13)) return 2+13 = 15 => completes the statement: return (2 + method(8)) return 4+15 = 19 => completes the statement: return (4 + method(5)) Therefore the call to method passing in 0, method(0), returns Recursively create a solution to printing intersecting diagonals to the screen, similar to an X. State the base case(s), recursive case(s), and recursive step(s) utilized in your solution. Also, discuss how your solution is moving from the start to the base case(s). If five were entered, the output would be: diagonals() analysis and design Base Case: when all rows are printed row == number Rec Case: not all rows printed row < number Rec Step: Handle all prints for this row, newline, Move to the next row

3 printcolumns(number, 0); System.out.println(); diagonals(number, row + 1); printcolumns() analysis and design Base Case: when all columns printed col == number Rec Case: not all columns printed col < number Rec Step: Handle the print for this column, move to the next column two different steps, based upon different sub cases if (col == row) print row value if (col == number - row) print row value else print blank space printcolumns(number, col + 1); class Diagonals { private int number; public Diagonals() { number = 5; public Diagonals(int number) { this.number = number; public void printdiagonals() { printdiagonals(1); public int getnumber() { return number; public void printdiagonals(int row) { if (row <= number) { printcolumns(row, 1); System.out.println(); printdiagonals(row + 1); public void printcolumns(int row, int col) { if (col <= number) { if (col == row col == (number - row) + 1) { System.out.print(row); else { System.out.print(" "); printcolumns(row, col + 1);

4 public void setnumber(int number) { this.number = number; 3. Create the class Vehicle. The class will contain a protected property of type String, the color of the vehicle. 4. Create the class Bike, a subclass of Vehicle. Bike will use the private property of type String, called energylevel, to represent the energy level the rider of the bike exerts. When a bike is ridden, the movement will burn calories, high, medium, and low energy levels burning 500, 250, and 100 calories respectively. Bike will contain the method move, which will simulate its movement. The method will not receive any parameters and will return int. 5. Create the class Car, a subclass of Vehicle. Car will use two private properties of type int, called distance and speed, to represent the distance the car has traveled and the speed of the travel. When the car is driven, the movement will take a certain amount of time, determined by dividing the distance by the speed. Car will contain the method move, which will simulate its movement. The method will not receive any parameters and will return an int representation of the time. class Vehicle { protected String color; public Vehicle () { color = new String(); public Vehicle(String color) { this.color = color; public String getcolor() { return color; public void setcolor (String c) { color = c; public String tostring() { return "Vehicle " + getcolor() + "\n"; class Bike extends Vehicle { private String energylevel;

5 // Create the standard constructors... public Bike(){ super(); energylevel = new String("medium"); public Bike(String energylevel, String color){ super(color); this.energylevel = energylevel; // Returns the calories consumed public int move(){ // Bike moves and burns calories if (energylevel == "high") return 500; else if (energylevel == "medium") return 250; else if (energylevel == "low") return 100; else return -1; public String tostring() { return super.tostring() + "Energy Level: " + energylevel + "\n"; // Create all other appropriate methods: // gets, sets, etc. class Car extends Vehicle { private int distance; private int speed; // Create the standard constructors... public Car(){ super(); distance = 10; // mi speed = 5; // mi/hr public Car(int distance, int speed, String color){ super(color); this.distance = distance; // mi this.speed = speed; // mi/hr

6 // Returns the amount of time that the car is driven public int move() { // Car moves and consumes time returns distance / speed; public String tostring() { return super.tostring() + "Distance: " + distance + "\n" + "Speed: " + speed + "\n"; // Create all other appropriate methods: // gets, sets, etc. 6. Create the UML diagram representing the classes and class relationships of Bike, Car, and Vehicle. Vehicle Bike Car Vehicle #color: String +Vehicle() +Vehicle(color: String) +getcolor(): String +setcolor(color: String): void +tostring(): String -energylevel: String Bike +Bike() +Bike(energyLevel: String) +getenergylevel(): String

7 +move(): int +setenergylevel(energylevel: String): void +tostring(): String -distance: int -speed: int Car +Car() +Car(distance: int, speed: int) +getdistance(): int +getspeed(): int +move(): int +setdistance(distance: int): void +setspeed(speed: int): void +tostring(): String 7. Create a class Model. The class will represent different types of car models. The class will have private properties of type String type and manufacturer. What methods are necessary within this class? Create all of them. 8. Update the class Car. It will now have private properties color type String, model type Model, and speed type double. The class will have a method called accelerate which receives the amount of increase in speed and a method decelerate with receives the amount of decrease in speed. What other methods are necessary within this class? Create all of them. 9. Create a class Dealership. The class will have a private property cars type Car an array. What other methods are necessary in this class? Create all of them. 10. Add the method public Car removecariterative(string color) to the class Dealership. The method will iteratively find if a car matching the color given is in the array of cars. If so, remove the car from the array and return the car found. As you search for the car having a specific color, what will your comparison be? Use compareto, equals, or equalsignorecase from the class String to compare. Refer to the class Dealership solution. 11. Add the method public Car removecarrecursive (String color) to the class Dealership. The method will recursively find if a car matching the color given is in the array of cars. If so, remove the car from the array and return the car found. State the base case(s), recursive

8 case(s), and recursive step(s) utilized in your solution. Also, discuss how your solution is moving from the start to the base case. 12. Create a driver program. In the driver, allow the user to create and add cars to the dealership. Create an instance of your car, your roommate's car, and your dream car. What other methods are necessary in this class? Create all of them. The following classes provide solutions to Problems 8 through 13. import java.util.scanner; class Model { private String manufacturer; private String type; public Model() { this.manufacturer = new String(); this.type = new String(); public Model(String manufacturer, String type) { this.manufacturer = manufacturer; this.type = type; public String getmanufacturer() { return manufacturer; public String gettype() { return type; public void setmanufacturer(string manufacturer) { this.manufacturer = manufacturer; public void settype(string type) { this.type = type; public String tostring() { return "The Model Manufacturer is " + manufacturer + "\n" + "The Model Type is " + type + "\n"; class Car { private String color; private Model model; private double speed; public Car() { this.color = new String();

9 this.model = new Model(); this.speed = 35; public Car(String color, Model model, double speed) { this.color = color; this.model = model; this.speed = speed; public void accelerate(int amount) { speed = speed + amount; public void decelerate(int amount) { if (speed < amount) { speed = 0; else { speed = speed - amount; public String getcolor() { return color; public Model getmodel() { return model; public double getspeed() { return speed; public void setmodel(model model) { this.model = model; public void setspeed(double speed) { this.speed = speed; public String tostring() { return "The Color of the Car is " + color + "\n" + model.tostring() + "The Speed of the Car is " + speed + "\n"; class Dealership { private Car cars[]; public Dealership() { cars = new Car[10]; public Dealership(Car cars[]) {

10 this.cars = cars; public boolean addcar(car car) { int index = 0; if (cars[cars.length - 1]!= null) { System.out.println("No spaces available for a new car"); return false; while (cars[index]!= null) { index++; cars[index] = car; return true; public Car[] getcars() { return cars; public void setcars(car cars[]) { this.cars = cars; public Car removecariterative(string color) { Car car = null; int i, index = 0; while (index < cars.length &&!color.equalsignorecase(cars[index].getcolor())) { index++; if (index == cars.length) { System.out.println("A " + color + " could not be found to remove."); else { car = cars[index]; for (i = index; i < cars.length - 1; i++) { cars[i] = cars[i + 1]; cars[cars.length - 1] = null; System.out.println("This car has been removed.\n" + car.tostring()); return car; public Car removecarrecursive(string color) { Car car = null;

11 int index = findcarrecursive(color, 0); if (index >= 0 && index < cars.length) { car = cars[index]; shiftcars(index); System.out.println("This car has been removed.\n" + car.tostring()); return car; public int findcarrecursive(string color, int index) { if (index >= cars.length) { return cars.length; else if (color.equalsignorecase(cars[index].getcolor())) { return index; else { return findcarrecursive(color, index + 1); public void shiftcars(int index) { if (index >= cars.length - 1) { cars[cars.length - 1] = null; else { cars[index] = cars[index + 1]; shiftcars(index + 1); public String tostring() { int i = 0; String data = new String("The cars at the" + "dealership are:\n"); while (i < cars.length && cars[i]!= null) { data = data.concat("car #" + (i + 1) + "\n"); data = data.concat(cars[i].tostring()); i++; return data; class Driver { public static void main(string args[]) { boolean loop = true; char choice;

12 Dealership dealership = new Dealership(); Diagonals diagonals = new Diagonals(); Scanner scanner = new Scanner(System.in); dealership.addcar(new Car("blue", new Model("Honda", "Accord"), 75)); dealership.addcar(new Car("red", new Model("Ford", "F150"), 50)); dealership.addcar(new Car("green", new Model("Ford", "Mustang"), 25)); while (loop) { System.out.println("(a) Print Diagonals"); System.out.println("(b) Add a Car"); System.out.println("(c) Remove a Car Iterative"); System.out.println("(d) Remove a Car Recursive"); System.out.println("(e) Print all Car data"); System.out.println("(q) Quit"); System.out.print("Select an Option: "); choice = scanner.nextline().charat(0); if (choice == 'a') { System.out.print("Enter the number of rows " + "in the diagonals: "); diagonals.setnumber(integer.parseint( scanner.nextline())); diagonals.printdiagonals(); if (choice == 'b') { System.out.print("Enter the color of the car: "); String color = scanner.nextline(); System.out.print("Enter the manufacturer " + "of the car: "); String manufacturer = scanner.nextline(); System.out.print("Enter the type of the car: "); String type = scanner.nextline(); System.out.print("Enter the speed of the car: "); double speed = Double.parseDouble(scanner.nextLine()); dealership.addcar(new Car(color, new Model(manufacturer, type), speed)); if (choice == 'c') { System.out.print("Enter the color of " + "the car to remove iteratively: "); dealership.removecariterative(scanner.nextline());

13 if (choice == 'd') { System.out.print("Enter the color of " + "the car to remove recursively: "); dealership.removecarrecursive(scanner.nextline()); if (choice == 'e') { System.out.println(dealership.toString()); if (choice == 'q') { loop = false; 13. Analyze and design a solution to the problem of alarms and their subclasses. Consider, the classes Alarm, SmokeAlarm, ClockAlarm, and SecurityAlarm. The class Alarm will serve as a superclass to the other three classes. Since an alarm will need to ring or be sounded, and the decision to ring will be determined by different factors for each subclass, Alarm will be abstract and defer the implementation of the method ring to each subclass. The class SmokeAlarm will ring when the level of smoke detected in the area exceeds a defined threshold. Class properties will define the currentlevel and maxlevel of smoke. The class ClockAlarm will ring when a numeric time is reached. Two double class properties will the currenttime and ringtime. When the current time reaches the ring time, the alarm will sound. Note, a back up or second ring time can be tracked by using two properties: ringtime1 and ringtime2. The class SecurityAlarm will ring when an incorrect integer code sequence of 0, 1, 2,, 9 values is entered. The code sequence will be stored as an ArrayList of type Integer. The user entered code sequence will also be stored as an ArrayList of type Integer. If the two match, the alarm will not ring.