chore: Lab04

Lab04/.classpath

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+<?xml version="1.0" encoding="UTF-8"?>
+<classpath>
+	<classpathentry kind="src" path="src"/>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER"/>
+	<classpathentry kind="output" path="bin"/>
+</classpath>

Lab04/.project

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+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>Lab04</name>
+	<comment></comment>
+	<projects>
+	</projects>
+	<buildSpec>
+		<buildCommand>
+			<name>org.eclipse.jdt.core.javabuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+	</buildSpec>
+	<natures>
+		<nature>org.eclipse.jdt.core.javanature</nature>
+	</natures>
+</projectDescription>

Lab04/src/lab04/Lab04.java

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+package lab04;
+
+public class Lab04 {
+
+	public static void main(String[] args) {
+		Quiz quiz = new Quiz(new String[] { "5*5 =", "12-7 =", "9/3 =", "12+10 =", "55/5 =" },
+				new String[][] { { "25", "62", "11", "5" }, { "75", "5", "11", "3" }, { "1", "2", "3", "4" },
+						{ "55", "66", "77", "22" }, { "111", "1111", "1", "11" } },
+				new int[] { 0, 1, 2, 3, 3 });
+		quiz.start();
+	}
+
+}

Lab04/src/lab04/Question.java

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+package lab04;
+
+import java.awt.event.ActionEvent;
+import java.awt.event.ActionListener;
+
+import javax.swing.BoxLayout;
+import javax.swing.JButton;
+import javax.swing.JFrame;
+import javax.swing.JLabel;
+import javax.swing.JOptionPane;
+import javax.swing.JPanel;
+
+public class Question {
+	private int questionNumber;
+	private String question;
+	private String[] answers;
+	private int correct;
+	private QuestionResponseEventHandler responseHandler;
+
+	private JFrame frame;
+
+	public Question(int questionNumber, String question, String[] answers, int correct,
+			QuestionResponseEventHandler responseHandler) throws Exception {
+		this.questionNumber = questionNumber;
+		this.question = question;
+		this.answers = answers;
+		this.correct = correct;
+		this.responseHandler = responseHandler;
+
+		if (answers.length != 4) {
+			throw new Exception("Should be exactly 4 answers");
+		}
+		if (correct < 0 || correct > 3) {
+			throw new Exception("Correct answer should be valid");
+		}
+
+		this.renderForm();
+	}
+
+	private void renderForm() {
+		frame = new JFrame("Question #" + String.valueOf(this.questionNumber));
+
+		JPanel panel = new JPanel();
+		panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));
+
+		panel.add(new JLabel(question));
+
+		JPanel answers = new JPanel();
+
+		Question that = this;
+		for (int i = 0; i < 4; i++) {
+			JButton button = new JButton(this.answers[i]);
+			boolean isCorrect = i == correct;
+			button.addActionListener(new ActionListener() {
+				@Override
+				public void actionPerformed(ActionEvent e) {
+					that.handleAnswer(isCorrect);
+				}
+			});
+			answers.add(button);
+		}
+
+		panel.add(answers);
+
+		frame.add(panel);
+
+		frame.setSize(500, 150);
+		frame.setVisible(true);
+	}
+
+	private void handleAnswer(boolean isCorrect) {
+		if (isCorrect) {
+			JOptionPane.showMessageDialog(frame, "Your answer is correct!", "Hurray!", JOptionPane.INFORMATION_MESSAGE);
+		} else {
+			JOptionPane.showMessageDialog(frame, "Your answers is wrong. The correct is: " + this.answers[this.correct],
+					"Oof", JOptionPane.ERROR_MESSAGE);
+		}
+
+		this.frame.setVisible(false);
+		this.responseHandler.onResponse(isCorrect);
+	}
+}

Lab04/src/lab04/QuestionResponseEventHandler.java

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+package lab04;
+
+public interface QuestionResponseEventHandler {
+	public void onResponse(boolean isCorrect);
+}

Lab04/src/lab04/Quiz.java

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+package lab04;
+
+import javax.swing.JOptionPane;
+
+public class Quiz implements QuestionResponseEventHandler {
+	private String[] questions;
+	private String[][] answers;
+	private int[] correct;
+
+	private int answerCorrect;
+	private int currentQuestion;
+
+	public Quiz(String[] questions, String[][] answers, int[] correct) {
+		this.questions = questions;
+		this.answers = answers;
+		this.correct = correct;
+
+		this.answerCorrect = 0;
+		this.currentQuestion = -1;
+	}
+
+	public boolean start() {
+		if (this.currentQuestion == -1) {
+			this.nextQuestion();
+			return true;
+		}
+
+		return false;
+	}
+
+	private void nextQuestion() {
+		this.currentQuestion++;
+
+		if (this.currentQuestion >= this.questions.length) {
+			this.finishQuiz();
+			return;
+		}
+
+		try {
+			new Question(this.currentQuestion + 1, this.questions[this.currentQuestion],
+					this.answers[this.currentQuestion], this.correct[this.currentQuestion], this);
+		} catch (Exception e) {
+			JOptionPane.showMessageDialog(null, "ERROR: Invalid question: " + e.getMessage());
+			this.nextQuestion();
+		}
+	}
+
+	private void finishQuiz() {
+		JOptionPane.showMessageDialog(null,
+				"Correct answers: " + String.valueOf(this.answerCorrect) + "/" + String.valueOf(this.questions.length)
+						+ "   |   " + String.valueOf(this.answerCorrect * 100 / this.questions.length) + "%",
+				"Quiz completed!", JOptionPane.QUESTION_MESSAGE);
+	}
+
+	@Override
+	public void onResponse(boolean isCorrect) {
+		if (isCorrect) {
+			this.answerCorrect++;
+		}
+
+		this.nextQuestion();
+	}
+}