BankManagementApp.java

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

class BankAccount {
    private String accountNumber;
    private String accountHolder;
    private double balance;

    public BankAccount(String accountNumber, String accountHolder) {
        this.accountNumber = accountNumber;
        this.accountHolder = accountHolder;
        this.balance = 0.0;
    }

    public String getAccountNumber() {
        return accountNumber;
    }

    public String getAccountHolder() {
        return accountHolder;
    }

    public double getBalance() {
        return balance;
    }

    public void deposit(double amount) {
        if (amount > 0) {
            balance += amount;
            System.out.println("Deposited: $" + amount);
        } else {
            System.out.println("Invalid amount for deposit.");
        }
    }

    public void withdraw(double amount) {
        if (amount > 0 && amount <= balance) {
            balance -= amount;
            System.out.println("Withdrawn: $" + amount);
        } else {
            System.out.println("Invalid amount or insufficient balance.");
        }
    }

    @Override
    public String toString() {
        return "Account Number: " + accountNumber +
                "\nAccount Holder: " + accountHolder +
                "\nBalance: $" + balance;
    }
}

public class BankManagementApp {
    private static ArrayList<BankAccount> accounts = new ArrayList<>();
    private static Scanner scanner = new Scanner(System.in);

    public static void main(String[] args) {
        while (true) {
            System.out.println("\nBank Management System");
            System.out.println("1. Create Account");
            System.out.println("2. Deposit");
            System.out.println("3. Withdraw");
            System.out.println("4. Check Balance");
            System.out.println("5. Exit");
            System.out.print("Enter your choice: ");

            int choice = scanner.nextInt();
            scanner.nextLine(); // Consume the newline character

            switch (choice) {
                case 1:
                    createAccount();
                    break;
                case 2:
                    deposit();
                    break;
                case 3:
                    withdraw();
                    break;
                case 4:
                    checkBalance();
                    break;
                case 5:
                    System.out.println("Exiting the application.");
                    System.exit(0);
                default:
                    System.out.println("Invalid choice. Please try again.");
            }
        }
    }

    private static void createAccount() {
        System.out.print("Enter Account Number: ");
        String accountNumber = scanner.nextLine();
        System.out.print("Enter Account Holder Name: ");
        String accountHolder = scanner.nextLine();
        BankAccount account = new BankAccount(accountNumber, accountHolder);
        accounts.add(account);
        System.out.println("Account created successfully.");
    }

    private static void deposit() {
        System.out.print("Enter Account Number: ");
        String accountNumber = scanner.nextLine();
        BankAccount account = findAccount(accountNumber);
        if (account != null) {
            System.out.print("Enter Deposit Amount: $");
            double amount = scanner.nextDouble();
            account.deposit(amount);
        } else {
            System.out.println("Account not found.");
        }
    }

    private static void withdraw() {
        System.out.print("Enter Account Number: ");
        String accountNumber = scanner.nextLine();
        BankAccount account = findAccount(accountNumber);
        if (account != null) {
            System.out.print("Enter Withdraw Amount: $");
            double amount = scanner.nextDouble();
            account.withdraw(amount);
        } else {
            System.out.println("Account not found.");
        }
    }

    private static void checkBalance() {
        System.out.print("Enter Account Number: ");
        String accountNumber = scanner.nextLine();
        BankAccount account = findAccount(accountNumber);
        if (account != null) {
            System.out.println(account);
        } else {
            System.out.println("Account not found.");
        }
    }

    private static BankAccount findAccount(String accountNumber) {
        for (BankAccount account : accounts) {
            if (account.getAccountNumber().equals(accountNumber)) {
                return account;
            }
        }
        return null;
    }
}