Task1 VirtuNexa Internship

import java.util.*;

public class MathQuizExpenseManager{
    private static final Scanner scanner = new Scanner(System.in);
    private static final List<Expense> expenses = new ArrayList<>();
    private static int score;

    public static void main(String[] args){
        while (true){
            showMainMenu();
        }
    }

    private static void showMainMenu() {
        System.out.println("\n=== Main Menu ===");
        System.out.println("1. Math Quiz");
        System.out.println("2. Expense Management");
        System.out.println("3. Exit");
        System.out.print("Choose an option: ");
        int choice = scanner.nextInt();

        if (choice == 1) startMathQuiz();
        else if (choice == 2) manageExpenses();
        else if (choice == 3) {
            System.out.println("Exiting application. Goodbye!");
            System.exit(0);
        } else {
            System.out.println("Invalid choice. Try again.");
        }
    }

    private static void startMathQuiz() {
        Random random = new Random();
        score = 0;

        while (true) {
            int num1 = random.nextInt(10) + 1;
            int num2 = random.nextInt(10) + 1;
            char operator = "+-*".charAt(random.nextInt(3));
            int correctAnswer = switch (operator) {
                case '+' -> num1 + num2;
                case '-' -> num1 - num2;
                default -> num1 * num2;
            };

            System.out.printf("Solve: %d %c %d = ?\n", num1, operator, num2);
            if (scanner.nextInt() == correctAnswer) {
                System.out.println("Correct!");
                score++;
            } else {
                System.out.printf("Wrong! The correct answer was %d.\n", correctAnswer);
            }
            System.out.println("\n1. Next Question\n2. Back to Main Menu");
            System.out.print("Choose an option: ");
            int choice = scanner.nextInt();
            if (choice == 2) {
                System.out.printf("Quiz Over! Your Score: %d\n", score);
                break;
            }
        }
    }

    private static void manageExpenses(){
        while (true) {
            System.out.println("\n=== Expense Management ===");
            System.out.println("1. Add Expense\n2. View Expenses\n3. Edit Expense\n4. Delete Expense\n5. Back");
            System.out.print("Choose an option: ");
            int choice = scanner.nextInt();
            scanner.nextLine();

            if (choice == 1) addExpense();
            else if (choice == 2) viewExpenses();
            else if (choice == 3) editExpense();
            else if (choice == 4) deleteExpense();
            else if (choice == 5) return;
            else System.out.println("Invalid choice. Try again.");
        }
    }

    private static void addExpense(){
        System.out.print("Description: ");
        String description = scanner.nextLine();
        System.out.print("Amount: ");
        double amount = scanner.nextDouble();
        scanner.nextLine();
        System.out.print("Category: ");
        String category = scanner.nextLine();

        expenses.add(new Expense(description, amount, category));
        System.out.println("Expense added!");
    }

    private static void viewExpenses() {
        if (expenses.isEmpty()) {
            System.out.println("No expenses recorded.");
            return;
        }
        System.out.println("\nExpenses:");
        for (int i = 0; i < expenses.size(); i++) {
            System.out.printf("%d. %s - $%.2f [%s]\n", i + 1, expenses.get(i).description, expenses.get(i).amount, expenses.get(i).category);
        }
    }

    private static void editExpense(){
        viewExpenses();
        if (expenses.isEmpty()) return;

        System.out.print("Enter expense number to edit: ");
        int index = scanner.nextInt() - 1;
        scanner.nextLine();
        if (index < 0 || index >= expenses.size()) {
            System.out.println("Invalid number.");
            return;
        }

        System.out.print("New description: ");
        expenses.get(index).description = scanner.nextLine();
        System.out.print("New amount: ");
        expenses.get(index).amount = scanner.nextDouble();
        scanner.nextLine();
        System.out.print("New category: ");
        expenses.get(index).category = scanner.nextLine();

        System.out.println("Expense updated!");
    }

    private static void deleteExpense(){
        viewExpenses();
        if (expenses.isEmpty()) return;

        System.out.print("Enter expense number to delete: ");
        int index = scanner.nextInt() - 1;
        if (index < 0 || index >= expenses.size()) {
            System.out.println("Invalid number.");
            return;
        }

        expenses.remove(index);
        System.out.println("Expense deleted!");
    }
}

class Expense{
    String description;
    double amount;
    String category;

    Expense(String description, double amount, String category){
        this.description = description;
        this.amount = amount;
        this.category = category;
    }
}