Main.java

import java.util.*;
class ATM {
    private double balance = 10000000.31;
    private int pin = 1234;
    private int attempts = 0;
    private final int MAX_ATTEMPTS = 3;
    private List<String> transactions = new ArrayList<>();
    private Scanner sc = new Scanner(System.in);
    public void checkPin() {
        while (attempts < MAX_ATTEMPTS) {
            System.out.print("Enter PIN: ");
            int enteredPin = sc.nextInt();

            if (enteredPin == pin) {
                menu();
                return;
            } else {
                attempts++;
                System.out.println("Invalid PIN. Attempts left: " + (MAX_ATTEMPTS - attempts));
            }
        }
        System.out.println("Account locked due to multiple incorrect attempts.");
    }
    public void menu() {
        while (true) {
            System.out.println("\n1. Check Balance");
            System.out.println("2. Withdraw");
            System.out.println("3. Deposit");
            System.out.println("4. Transfer");
            System.out.println("5. Transaction History");
            System.out.println("6. Change PIN");
            System.out.println("7. Fast Cash");
            System.out.println("8. Exit");
            System.out.print("Select option: ");
            int choice = sc.nextInt();
            switch (choice) {
                case 1: checkBalance(); break;
                case 2: withdraw(); break;
                case 3: deposit(); break;
                case 4: transfer(); break;
                case 5: showTransactions(); break;
                case 6: changePin(); break;
                case 7: fastCash(); break;
                case 8: return;
                default: System.out.println("Invalid option.");
            }
        }
    }
    public void checkBalance() {
        System.out.println("Current balance: " + balance);
    }
    public void withdraw() {
        System.out.print("Enter amount: ");
        double amount = sc.nextDouble();
        if (amount <= 0) {
            System.out.println("Invalid amount.");
            return;
        }
        if (amount > balance) {
            System.out.println("Insufficient balance.");
        } else {
            balance -= amount;
            transactions.add("Withdraw: " + amount);
            System.out.println("Withdrawal successful.");
            System.out.println("Updated balance: " + balance);
        }
    }
    public void deposit() {
        System.out.print("Enter amount: ");
        double amount = sc.nextDouble();
        if (amount <= 0) {
            System.out.println("Invalid amount.");
            return;
        }
        balance += amount;
        transactions.add("Deposit: " + amount);
        System.out.println("Deposit successful.");
        System.out.println("Updated balance: " + balance);
    }
    public void transfer() {
        System.out.print("Enter account number: ");
        long accountNumber = sc.nextLong();
        System.out.print("Enter amount: ");
        double amount = sc.nextDouble();
        if (amount > balance) {
            System.out.println("Insufficient balance.");
        } else {
            balance -= amount;
            transactions.add("Transfer: " + amount + " to A/C " + accountNumber);
            System.out.println("Transfer successful.");
        }
    }
    public void showTransactions() {
        if (transactions.isEmpty()) {
            System.out.println("No transactions available.");
            return;
        }

        System.out.println("Transaction History:");
        for (String t : transactions) {
            System.out.println(t);
        }
    }
    public void changePin() {
        System.out.print("Enter current PIN: ");
        int currentPin = sc.nextInt();
        if (currentPin == pin) {
            System.out.print("Enter new PIN: ");
            pin = sc.nextInt();
            System.out.println("PIN updated successfully.");
        } else {
            System.out.println("Incorrect PIN.");
        }
    }
    public void fastCash() {
        System.out.println("1. 500");
        System.out.println("2. 1000");
        System.out.println("3. 5000");
        System.out.print("Choose option: ");
        int option = sc.nextInt();
        int amount = 0;
        if (option == 1) amount = 500;
        else if (option == 2) amount = 1000;
        else if (option == 3) amount = 5000;
        else {
            System.out.println("Invalid choice.");
            return;
        }
        if (amount > balance) {
            System.out.println("Insufficient balance.");
        } else {
            balance -= amount;
            transactions.add("Fast Cash: " + amount);
            System.out.println("Please collect your cash.");
        }
    }
}
public class Main {
    public static void main(String[] args) {
        ATM atm = new ATM();
        atm.checkPin();
    }
}