ATM.java

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

public class ATM {
    public static Scanner sc = new Scanner(System.in);
    public static ArrayList<String> list = new ArrayList<>();

    // "transac" function displays the transaction history for the user
    public static void transac(int balance) {
        for (String i : list) {
            System.out.println(i);
        }
        ask(balance);
    }

    // "login" function checks if the given username and pin are valid
    public static void login(String username, int pin) {
        if (username.contains("Jack") && pin == 1010) {
            list.add("Logged in");
            ask(6000);
        } else {
            System.out.println("Enter valid info!");
            System.out.print("Username followed by pin seperated with a space: ");
            login(sc.next(), sc.nextInt());
        }
    }

    // "withdraw" function allows the user to withdraw a specified amount from their
    // account
    public static void withdraw(int balance, int amount) {
        if (amount <= balance && amount >= 0) {
            balance -= amount;
            System.out.println("Transaction successful, Current balance is " + balance);
            list.add("Rupee/'s " + amount + " withdrawn.");
            ask(balance);
        } else {
            System.out.print("Enter a valid amount(greater than equal to 0): ");
            withdraw(balance, sc.nextInt());
        }
    }

    // "deposit" to deposit a specified amount into their account
    public static void deposit(int balance, int amount) {
        if (amount >= 0) {
            balance += amount;
            System.out.println("Transaction successful, Current balance is " + balance);
            list.add(amount + " ruppee/'s deposited!");
            ask(balance);
        } else {
            System.out.print("Enter a valid amount(greater than equal to 0): ");
            deposit(balance, sc.nextInt());
        }
    }

    // "transfer" function allows the user to transfer a specified amount to another
    // user's account
    public static void transfer(int balance, int amount) {
        if ((amount <= balance) && (amount >= 0)) {
            System.out.print("Enter reciver's username: ");
            String accname = sc.next();
            balance -= amount;
            System.out.println(amount + " rupee/s sent to " + accname);
            System.out.println("Transaction successful, Current balance is " + balance);
            list.add(amount + " transfered to account " + accname);
            ask(balance);
        } else {
            System.out.print("Enter a valid amount(greater than equal to 0): ");
            transfer(balance, sc.nextInt());
        }
    }

    // "quit" to exit the program
    public static void quit(int balance, char qresponse) {
        if (qresponse == 'y' || qresponse == 'Y') {
            System.out.println("---------------Logged out---------------");
            System.out.println();
        } else
            ask(balance);
    }

    // "ask" function presents the user with a list of options and allows them to
    // choose one of the actions
    public static void ask(int bal) {
        System.out.println("----------------------------------------");
        System.out.println();
        System.out.println("1) Transaction History");
        System.out.println("2) Withdraw");
        System.out.println("3) Deposit");
        System.out.println("4) Transfer");
        System.out.println("5) Quit");
        System.out.print("Choose one of the following actions: ");
        int opt = sc.nextInt();
        System.out.println();
        if (1 > opt || opt > 5) {
            System.out.println("Enter valid input!");
            ask(bal);
        } else {
            switch (opt) {
                case 1:
                    System.out.println("----------Transaction history!----------");
                    transac(bal);
                    break;

                case 2:
                    System.out.print("Enter amount to be withdrawn: ");
                    withdraw(bal, sc.nextInt());
                    break;

                case 3:
                    System.out.print("Enter amount to be deposited: ");
                    deposit(bal, sc.nextInt());
                    break;

                case 4:
                    System.out.print("Enter amount to be transfered: ");
                    transfer(bal, sc.nextInt());
                    break;

                case 5:
                    System.out.print("Do you want to exit?(Yes/No): ");
                    char qresponse = sc.next().charAt(0);
                    quit(bal, qresponse);
                    break;
            }
        }
    }

    public static void main(String[] args) {
        System.out.println();
        // Use username as Given'Jack'
        System.out.println("Use pin as '1010 for testing!");
        System.out.println("---------------**Login!**---------------");
        System.out.print("Enter user name: ");
        String username = sc.next();
        System.out.print("Enter pin: ");
        int pin = sc.nextInt();
        login(username, pin);
    }
}