Part 1. Programming Output [Polymorphism]

Transcription

1 KINGDOM OF SAUDI ARABIA Ministry of Higher Education Prince Sultan University College of Computer and Information Sciences المملكة العربية السعودية وزارة التعليم العالي جامعة الا مري سلطان كلية علوم الحاسب والمعلومات Exam: Final Exam Course: Programming II (CS102) Duration: 120 minutes Notes: Only Java Collection Framework API smarmy provided by the instructor is authorized. Confusing answers will be counted zero. Instructor: Dr. Anis Koubaa Term: Fall Dec 2013 Number of pages: 12 pages Grading: Part 1 Polymorphism 6 points Part 2 Java Collections 4 points Part 3 Coding 10 points Part 4 Programming Problem 20 points Student ID: Student Name: Part 1. Programming Output [Polymorphism] Grade: 6 points Duration: 20 minutes class Car extends FourWheelVehicle { public void b() { System.out.println("Car b"); super.b(); public void c() { System.out.println("Car c"); class FourWheelVehicle extends Vehicle { public void b() { System.out.println("FourWheelVehicle b"); a(); class Bus extends FourWheelVehicle { public void a() { System.out.println("Bus a"); public void c() { b(); System.out.println("Bus c"); class Vehicle { public void a() { System.out.println("Vehicle a"); In the table below, indicate in the right-hand column the output produced by the statement in the left-hand column. If the statement causes an error (compilation or logical), fill in the right-hand column with "error" to indicate this. For each statement, the response must be fully correct or will be counted as completely wrong. Partial answers are not accepted. vechile1.a(); vechile1.b(); fwvehicle.a(); fwvehicle.b(); vehicle2.a(); ob.a(); ((Car) vechile1).b(); 0.5 pt 1 pt 0.5 pt 1 pt 0.5 pt 0.5 pt 1 pt 1 pt public void b() { System.out.println("Vehicle b"); public class Output { public static void main(string [] args){ Vehicle vechile1 = new Car(); FourWheelVehicle fwvehicle = new Bus(); Vehicle vehicle2 = new FourWheelVehicle(); Object ob = new FourWheelVehicle(); ((Bus) fwvehicle).c(); Dr. Anis Koubaa 1/12 December 2013

2 Part 2. Programming Output [Java Collection Framework] Grade: 04 points Duration: 20 minutes Program 1. Write the output of the following program. (2 points) public class JCF { public static void main(string[] args) { // Create a hash countryset Set<String> countryset = new TreeSet<String>(); // Add strings to the countryset countryset.add("saudi Arabia"); countryset.add("tunisia"); countryset.add("egypt"); countryset.add("algeria"); countryset.add("emirates"); countryset.add("jordan"); System.out.println("Countries Set: " + countryset ); List <String> countrylist = new LinkedList (countryset); System.out.print("Countries List: "); // Obtain an iterator for the hash countryset ListIterator<String> iterator = countrylist.listiterator(countrylist.size()); while (iterator.hasprevious()) { System.out.print(iterator.previous().toUpperCase()+" "); Dr. Anis Koubaa 2/12 December 2013

3 Program 2. Write the output of the following program. (2 points) public class ComparatorOutput { public static void main(string[] args) { Set<GeometricObject> set = new TreeSet<GeometricObject>(new GeometricObjectComparator()); set.add(new Rectangle(4, 5, "R1")); new Circle(40, "C1"); set.add(new Circle(40, "C2")); set.add(new Rectangle(4, 1, "R2")); // Display geometric objects in the tree set System.out.println("A set of geometric objects"); for (GeometricObject element: set) System.out.println("name: "+element.name+", area = " + element.area()); abstract class GeometricObject { String name; public GeometricObject (String n){ name=n; public abstract double area(); class Circle extends GeometricObject { double radius; public Circle (double r, String n){ super(n); radius=r; public double area(){ return radius*radius; class Rectangle extends GeometricObject { double width; double length; public Rectangle(double w, double l, String n){ super (n); width=w; length=l; public double area(){ return width*length; class GeometricObjectComparator implements Comparator<GeometricObject>{ public int compare(geometricobject o1, GeometricObject o2){ return (int) (o1.area()-o2.area()); Dr. Anis Koubaa 3/12 December 2013

4 KINGDOM OF SAUDI ARABIA Ministry of Higher Education Prince Sultan University College of Computer and Information Sciences المملكة العربية السعودية وزارة التعليم العالي جامعة الا مري سلطان كلية علوم الحاسب والمعلومات Part 3 : Coding Grade: 10 points Duration: 30 minutes [Java Collection Framework] 1. Write a method static void parsestring (String input) that has one parameter input, which is a String that represents a sentence of several words. The words in the sentence are separated by a space. The method performs the following instructions (you must use static methods of the class Collections): The method first converts the String sentence into an array of string words using the method split(string s) of the class String. The array is converted to an ArrayList using the static method aslist()of the class Arrays. The array list is sorted. Using an iterator, the method displays each word in the ArrayList and its frequency (number of occurrences. (5 points) 2. Write a method Map<String, Integer> Queue2Map (PriorityQueue <String> pq) that converts a queue of String objects into a Map of String objects (i.e. words). The method has one parameter pq, which is a queue of String values. The method must return a TreeMap that contains the String values of the queue and their frequencies (number of occurrence of each word). (5 points) Dr. Anis Koubaa 4/12 December 2013

5 KINGDOM OF SAUDI ARABIA Ministry of Higher Education Prince Sultan University College of Computer and Information Sciences المملكة العربية السعودية وزارة التعليم العالي جامعة الا مري سلطان كلية علوم الحاسب والمعلومات Part 4. Programming Problem Grade: 20 points Duration: 50 minutes As in the project, you will develop some Java classes and methods for finding a path in a grid map from an initial position to a target position in a grid map. The grid map is defined as a 2D array of cells as shown in Figure 1 below G S Figure 1. map model A cell can be free (white color) or occupied with an obstacle (black color). S represents the starting position and G the goal position to which a path must be found. The objective is to find a path from the starting cell S in position (Xs,Ys) to the goal cell G in position (Xg, Yg). In Figure 1, the position of S is (4,0) and the position of G is (0,7). The path is shown in green color in Figure 1 as illustration. The path is the sequence of cells {(4,0), (4,1), (4,2), (3,2), (3,3), (2,3),(2,4), (2,6), (2,7), (1,7), (0,7). The class Cell and the Class GridMap are provided in the Appendices 1 and 2 (see last pages). Class Path Grade: 9 points You are requested to create the class Path with the following attributes and methods. It also implements the interface Comparable, where two paths are compared based on their lengths. Member private List <Cell> path public path () public void addcell (Cell C) public void addcell (Cell C, int index) public void removecell (Cell C) public int getlength() public String tostring () Description Specifies the path as a list if cells. A default constructor that create a new ArrayList for the path attribute Adds a new Cell to the end of the path Adds a new Cell to the end of the path at the specified index i Removes the Cell C from the path Returns the length of the path. The length of the path is the number of cells in the array. Returns the area of the Real Estate Question: Write the class Path and make it Comparable by comparing two objects based on their length. Use accessors and mutators only when needed. (9 points) Dr. Anis Koubaa 5/12 December 2013

6 Dr. Anis Koubaa 6/12 December 2013

7 KINGDOM OF SAUDI ARABIA Ministry of Higher Education Prince Sultan University College of Computer and Information Sciences المملكة العربية السعودية وزارة التعليم العالي جامعة الا مري سلطان كلية علوم الحاسب والمعلومات Construct a Path Grade: 11 points Question: Write a static method constructpathmanually (). The method takes as parameter, a grid map gridmap, a start cell, a goal cell and number of trial nbtrials. These are the requirements of the method: The method must display an output exactly the same as the sample output provided in the Appendix 3 (see last pages). (1 points) It prints Hello in Path Finder Game, then the start position, the goal position, the grid map, and the initial path, as specified in the sample output (see last pages). The method must create a path that initially contains the start cell. (1 point) The method must check whether the start and the goals cell are both free cells. If any of them is not a free cell, the method must return the value -1 and exit. Use the method isfree(map m) of the Class Cell. (1 points) The method will ask the user to enter the next Cell until it reaches the goal or he enters a certain number of wrong trials greater than nbtrial parameter. In each trial, the user is prompted this message Enter the next Cell in the form x,y: " The user enters the x and y of the next Cell. (1 point) If the cell input by the user is free, (1 point) o The cell is added to the path (1 point) o If the new path after adding the cell is not feasible (i.e. cell not a neighbor) then, (1 point) It is removed from the path (1 point) The following message is displayed ( Your proposed cell is not accepted in the path. Choose a neighbor cell! ) (1 point) Else, if the cell is not free, the following message is displayed ( Your suggested cell is not accepted in the path because it is an OBSTACLE. Choose a FREE neighbor cell! ) (1 point) After the path is found or the number of trials is reached, the program displays the path and its length and the number of incorrect trials similar to (see sample output in the last pages): (1 point) Your Path is: [(0, 0), (1, 1), (1, 2), (2, 2)] with length 4 You made: 1 incorrect trials! Dr. Anis Koubaa 7/12 December 2013

8 Dr. Anis Koubaa 8/12 December 2013

9 Appendix 1. Class Cell public class Cell implements Comparable <Cell>{ private int x; private int y; public Cell (int x, int y){ setx(x); sety(y); public void setx(int x){ this.x=x; public int getx(){ return x; public void sety(int y){ this.y=y; public int gety(){ return y; public double getdistance(cell C){ return Math.sqrt(Math.pow(getX()-C.getX(),2)+Math.pow(getY()-C.getY(),2)); public boolean isneighbor(cell C){ if ((Math.pow((this.x-C.x),2)>1)&&((Math.pow((this.y-C.y),2)>1))) return false; return true; public boolean isfree (GridMap m){ if (m.getgridmap()[x][y]==0) return true; return false; public static double getdistance (Cell C1, Cell C2){ return Math.sqrt(Math.pow(C1.getX()-C2.getX(),2)+Math.pow(C1.getY()- C2.getY(),2)); public String tostring(){ return String.format("(%2d,%2d)", getx(), gety()); public int compareto(cell C){ //if both x and y are equal return 0 if ((this.getx()==c.getx())&&(this.gety()==c.gety())) return 0; else if ((this.getx()<c.getx())) return 1; return -1; Dr. Anis Koubaa 9/12 December 2013

10 Appendix 2. Class GridMap public class GridMap { private int width; private int length; private int [] [] gridmap; public GridMap (int w, int l, int [] [] gm){ setwidth(w); setlength(l); setgridmap(gm); public GridMap (int w, int l){ setwidth(w); setlength(l); gridmap = new int [w][l]; public void loadmap(file f){ //load a map from a file public int getwidth(){ return width; public void setwidth(int w){ width = w; public int getlength(){ return length; public void setlength(int l){ length = l; public int [] [] getgridmap(){ return gridmap; public void setgridmap(int [][] gm){ gridmap = gm; public String tostring(){ String s = "Grid Map: \n"; for (int i = 0; i<getwidth(); i++){ for (int j = 0; j<getlength(); j++){ s = s + String.format("%5d", gridmap[i][j]); s=s+"\n"; return s; Dr. Anis Koubaa 10/12 December 2013

11 KINGDOM OF SAUDI ARABIA Ministry of Higher Education Prince Sultan University College of Computer and Information Sciences المملكة العربية السعودية وزارة التعليم العالي جامعة الا مري سلطان كلية علوم الحاسب والمعلومات Appendix 3. Three Sample Outputs Sample Output 1 PATH FINDER GAME Hello in Path Finder Game start position: ( 0, 0) goal position: ( 2, 2) grid map: Grid Map: initial path: [( 0, 0)] Enter the next Cell in the form x,y: 1,1 current Cell ( 1, 1) path: [( 0, 0), ( 1, 1)] Enter the next Cell in the form x,y: 3,3 Your proposed cell is not accepted in the path. Choose a neighbor cell! path: [( 0, 0), ( 1, 1)] Enter the next Cell in the form x,y: 5,6 Your proposed cell is not accepted in the path. Choose a neighbor cell! path: [( 0, 0), ( 1, 1)] Enter the next Cell in the form x,y: 1,0 Your suggested cell is not accepted in the path because it is an OBSTACLE. Choose a FREE neighbor cell! Your Path is: [( 0, 0), ( 1, 1)] with length 2 You made: 3 incorrect trials! Sample Output 2 PATH FINDER GAME Hello in Path Finder Game start position: ( 0, 0) goal position: ( 2, 2) grid map: Grid Map: initial path: [( 0, 0)] Enter the next Cell in the form x,y: 1,0 Your suggested cell is not accepted in the path because it is an OBSTACLE. Choose a FREE neighbor cell! Enter the next Cell in the form x,y: 1,1 current Cell ( 1, 1) path: [( 0, 0), ( 1, 1)] Enter the next Cell in the form x,y: 1,2 current Cell ( 1, 2) path: [( 0, 0), ( 1, 1), ( 1, 2)] Enter the next Cell in the form x,y: 2,2 current Cell ( 2, 2) path: [( 0, 0), ( 1, 1), ( 1, 2), ( 2, 2)] Your Path is: [( 0, 0), ( 1, 1), ( 1, 2), ( 2, 2)] with length 4 You made: 1 incorrect trials! Dr. Anis Koubaa 11/12 December 2013

12 Sample Output 3 Hello in Path Finder Game start position: ( 0, 0) goal position: ( 2, 2) grid map: Grid Map: initial path: [( 0, 0)] start or goal is an obstacle, quit program: [( 0, 0)] Dr. Anis Koubaa 12/12 December 2013