Bank.java

import java.util.ArrayList;

class Bank {
    private ArrayList<Account> accounts = new ArrayList<>();

    public void createAccount(Account account){
        accounts.add(account);
        System.out.println("Account created successfully!");
    }

    public Account findAccount(int accountNumber){
        for(Account ac : accounts){
            if(ac.getAccountNumber() == accountNumber){
                return ac;
            }
        }
        return null;
    }

    public Account authenticateUser(int accountNumber, int pin){
        Account account = findAccount(accountNumber);
        if(account != null && account.authenticate(pin))
            return account;
        return null;
    }

    public void depositToAccount(int accountNumber, double amount){
        Account account = findAccount(accountNumber);
        if(account == null){
            System.out.println("Account not found!");
            return;
        }

        account.deposit(amount);
    }

    public void withdrawFromAccount(int accountNumber, double amount){
        Account account = findAccount(accountNumber);
        if(account == null){
            System.out.println("Account not found!");
            return;
        }

        account.withdraw(amount);
    }

    public void displayAllAccounts(){
        if(accounts.isEmpty()){
            System.out.println("No Accounts Available!");
            return;
        }

        for(Account ac : accounts){
            ac.display();
        }
    }
}