ExpenseTracker.java

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Scanner;

public class ExpenseTracker {
    private static final String FILE_PATH = "expenses.txt";

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        ensureFileExists();
        System.out.println("\n === Welcome to the Expense Tracker ===");
        displayExpenses();

        do {
            System.out.println("\nChoose an action: ");
            System.out.println("1. Add a new expense");
            System.out.println("2. Delete an expense");
            System.out.println("3. Delete all expenses");
            System.out.println("4. Exit");
            System.out.print("Enter your choice: ");
            int choice = scanner.nextInt();

            switch(choice){
                case 1 -> addExpemse(scanner);
                case 2 -> deleteSpecificExpense(scanner);
                case 3 -> deleteAllExpenses();
                case 4 -> System.out.println("Exiting... \n Thank you for using the Expense Tracker!");
            }
        }
        while (choice != 4);
    }

    private static void ensureFileExists(){
        File file = new File(FILE_PATH);

        try {
            if (file.createNewFile()){
                System.out.println("No previous records found. A new expense file has been created.");

                FileWriter writer = new FileWriter(FILE_PATH);
                writer.write();
            }
        }
        catch (IOException e){
            System.out.println("Error creating the file");
            e.printStackTrace();
        }
    }

    private static void displayExpenses(){
        File file = new File(FILE_PATH);

        if (!file.exists() || file.length() == 0){
            System.out.println("No expenses found. Please add some expenses first.");
            return;
        }

        ArrayList<String> expenses = new ArrayList<>();
        try{
            Scanner fileScanner = new Scanner(file);
            while (fileScanner.hasNextLine()){
                expenses.add(fileScanner.nextLine());
            }
            catch (Exception e){
                System.out.println("Error reading this file.");
            }
        }
    }
}