CS111 Lab 3a:

Building OOP Applications

Exercise I: Build a Quiz Application

Build a QuizApp that allows the user to practice a subject by taking a quiz containing a series of basic fill-in-the blank questions as many times as they like. Each time the quiz is taken, the questions should be randomly shuffled to avoid the memorization of answers in a particular order. Once the user has read and answered a question, they receive a point if a response is correct otherwise they are given the proper answer.

Quiz applications are data driven. They rely on questions and answers to questions as primary game elements. Normally quiz data, such as the questions and answers, should be stored as external text files. In this application you will be asked to populate our quiz directly from your code file.

Goal 1: Build your app using the following Dependency and Aggregation Structure.

Goal 2: Use the following UML diagram (Unified Modeling Language) as your guide in building each class.

Question.java

public class Question {

// Data Members
    	private String question;
    	private String answer;

// -------------------------------------------------------------------
    	// Explicit constructor sets up the question by ensuring a question
    	// and answer.
    	// -------------------------------------------------------------------

public Question(String q, String a) {
    		question = q;
    		answer = a;
    	}

// -------------------------------------------------------------------
    	// Get the answer to this question.
    	// -------------------------------------------------------------------
    	public String getAnswer() {
    		return answer;
    	}

// -------------------------------------------------------------------
    	// Set the answer to this question.
    	// -------------------------------------------------------------------
    	public void setAnswer(String a) {
    		answer = a;
    	}

// -------------------------------------------------------------------
    	// Get the question.
    	// -------------------------------------------------------------------
    	public String getQuestion() {
    		return question;
    	}

// -------------------------------------------------------------------
    	// Set the question.
    	// -------------------------------------------------------------------
    	public void setQuestion(String q) {
    		question = q;
    	}

// -------------------------------------------------------------------
    	// Checks the answer to this question and returns a true if it is
    	// correct and a false otherwise
    	// -------------------------------------------------------------------
    	public boolean checkAnswer(String response) {
    		return answer.toLowerCase().equals(response.toLowerCase());
    	}

}

QuizEngine.java

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

public class QuizEngine {

// DATA MEMBERS
    	private ArrayList<Question> questionList;
    	private int nCorrectAnswers;
    	private Scanner in;

// -------------------------------------------------------------------
    	// Constructor:
    	// Instantiates questionList and initializes correctAnswers to zero.
    	// -------------------------------------------------------------------
    	public QuizEngine() {
    		questionList = new ArrayList<Question>();
    		nCorrectAnswers = 0;
    		in = new Scanner(System.in);
    	}

// -------------------------------------------------------------------
    	// Add a question to the questionList.
    	// -------------------------------------------------------------------
    	public void addQuestion(Question q) {
    		questionList.add(q);
    	}

// -------------------------------------------------------------------
    	// Shuffle the questionList.
    	// -------------------------------------------------------------------
    	public void shuffleQuestions() {
    		Collections.shuffle(questionList);
    	}

// -------------------------------------------------------------------
    	// Start the quiz: present questions one at a time,
    	// retrieve a response from the user,
    	// check for correctness.
    	// -------------------------------------------------------------------
    	public void start() {
    		nCorrectAnswers = 0;
    		System.out.println("\n\nSTARTING THE QUIZ\n");

for (int i = 0; i < questionList.size(); i++) {
    			System.out.println("Question " + (i + 1) + ": " + questionList.get(i).getQuestion());
    			System.out.print("\tAnswer: ");
    			String response = in.nextLine();
    			if (questionList.get(i).checkAnswer(response)) {
    				System.out.println("\tCorrect");
    				nCorrectAnswers++;
    			} else {
    				System.out.println("\tIncorrect");
    			}
    		}
    	}

// -------------------------------------------------------------------
    	// Return the results of the quiz.
    	// -------------------------------------------------------------------
    	public String getQuizResults() {
    		String outputResults = "Score: ";
    		outputResults += (int) ((double) nCorrectAnswers / questionList.size() * 100) + "%";
    		return outputResults;
    	}

}

MyMain.java

public class MyMain {

public static void main(String[] args) {
    		// TASK 1: CREATE FIVE QUESTIONS
    		Question q1 = new Question("What country gave us the word Shampoo?", "India");
    		Question q2 = new Question("How many people in the UK watch BW TV?", "10000");
    		Question q3 = new Question("Which fingernail grows the fastest?", "middle");
    		Question q4 = new Question("Who makes the best burrito in Redlands?", "Cucos");
    		Question q5 = new Question("What nationality was Reichelt?", "French");

// TASK 2: CREATE A QUIZ ENGINE OBJECT
    		QuizEngine quizEngine = new QuizEngine();

// TASK 3: POPULATE THE QUIZ ENGINE WITH THE QUESTIONS.
    		quizEngine.addQuestion(q1);
    		quizEngine.addQuestion(q2);
    		quizEngine.addQuestion(q3);
    		quizEngine.addQuestion(q4);
    		quizEngine.addQuestion(q5);

// TASK 4: ALLOW THE USER TO TAKE THE QUIZ AS MANY TIMES AS THEY WANT.
    		for (;;) {

// (A) SHUFFLE THE QUESTIONS
    			quizEngine.shuffleQuestions();

// (B) START THE QUIZ AND ASK ALL THE QUESTIONS
    			quizEngine.start();

// (C) DISPLAY THE RESULTS OF THE QUIZ
    			System.out.println(quizEngine.getQuizResults());
    		}
    	}

}

Exercise 2: Build the Sales Application shown below.

Construct a SalesItem class that stores a sales item being purchased. A SalesItem object can only be instantiated with explicit data values.
Construct a SalesSlip class that records and computes the sales total of a list of SalesItems.
The Sales Application uses a Graphical User Interface. The MyMain.java code, shown at the bottom of this page, can be used.

Classes needed: MyMain.java, SalesSlip.java, and SalesItem.java.


    import java.awt.event.ActionEvent;
    import java.awt.event.ActionListener;

    import javax.swing.JButton;
    import javax.swing.JFrame;
    import javax.swing.JLabel;
    import javax.swing.JTextArea;
    import javax.swing.JTextField;

    public class MyMain {

      // SPECIFY THE APPLICATION ELEMENTS: UI AND OBJECTS
      private static JFrame frame;
      private static JTextField itemTextField;
      private static JTextField costTextField;
      private static JTextField quantityTextField;
      private static JButton addItemBtn;
      private static JLabel totalSaleslbl;
      private static JTextArea salesTextArea;

      // OBJECT REPRESENTING A SALES SLIP
      private static SalesSlip salesSlip;

      // ********************************************************************************
      public static void main(String[] args) {

        // TASK 1: CREATE A APPLICATION WINDOW
        createGraphicWindow();

        // TASK 2: CREATE A SALESSLIP
        salesSlip = new SalesSlip();

        // TASK 3: ADD BUTTON LISTENER EVENT FOR ADDING SALES ITEMS
        addListenerEvent();

      }

      // ********************************************************************************
      public static void addListenerEvent() {
        addItemBtn.addActionListener(new ActionListener() {
          public void actionPerformed(ActionEvent e) {
            updateSalesSlip(); // HANDLES THE EVENT
          }
        });
      }

      // ********************************************************************************
      // EVENT HANDLER: CREATES A SALES ITEM AND UPDATES THE SALES SLIP
      public static void updateSalesSlip() {

        // TASK 1: COLLECT INPUT INFORMATION
        String item = itemTextField.getText();
        if (costTextField.getText().length() > 0 && quantityTextField.getText().length() > 0) {
          double price = Double.parseDouble(costTextField.getText());
          int quantity = Integer.parseInt(quantityTextField.getText());

          // TASK 2: ADD INPUT INFORMATION TO THE SALESSLIP AND DISPLAY
          salesTextArea.setText(salesTextArea.getText() + salesSlip.addSalesItem(item, price, quantity));

          // TASK 3: UPDATE THE SALESSLIP WITH THE NEW TOTAL
          totalSaleslbl.setText("Sales Total: $" + String.format("%.2f", salesSlip.getTotalSales()));

          // TASK 4: CLEAR THE INPUT TEXTFIELDS
          itemTextField.setText("");
          costTextField.setText("");
          quantityTextField.setText("");
        }

      }

      // ********************************************************************************
      // CREATES THE WINDOW FOR USERS TO INTERACT WITH
      private static void createGraphicWindow() {
        frame = new JFrame();
        frame.setBounds(20, 20, 450, 700);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().setLayout(null);

        JLabel lblTitle = new JLabel("Sales Application");
        lblTitle.setBounds(159, 6, 163, 16);
        frame.getContentPane().add(lblTitle);

        JLabel lbl1 = new JLabel("Item Name:");
        lbl1.setBounds(6, 69, 129, 16);
        frame.getContentPane().add(lbl1);
        itemTextField = new JTextField();
        itemTextField.setBounds(142, 64, 273, 26);
        frame.getContentPane().add(itemTextField);
        itemTextField.setColumns(10);

        JLabel lbl2 = new JLabel("Cost per Item : $");
        lbl2.setBounds(6, 102, 129, 16);
        frame.getContentPane().add(lbl2);
        costTextField = new JTextField();
        costTextField.setColumns(10);
        costTextField.setBounds(142, 97, 273, 26);
        frame.getContentPane().add(costTextField);

        JLabel lbl3 = new JLabel("Quantity : $");
        lbl3.setBounds(6, 133, 129, 16);
        frame.getContentPane().add(lbl3);
        quantityTextField = new JTextField();
        quantityTextField.setColumns(10);
        quantityTextField.setBounds(142, 128, 273, 26);
        frame.getContentPane().add(quantityTextField);

        addItemBtn = new JButton("Add Item to the Sales List");
        addItemBtn.setBounds(142, 164, 273, 29);
        frame.getContentPane().add(addItemBtn);

        totalSaleslbl = new JLabel("Total Sales: $0.00");
        totalSaleslbl.setBounds(6, 226, 336, 16);
        frame.getContentPane().add(totalSaleslbl);

        salesTextArea = new JTextArea("");
        salesTextArea.setBounds(35, 250, 400, 400);
        salesTextArea.setText("");
        frame.getContentPane().add(salesTextArea);

        frame.setVisible(true);

      }

    }