How would I change this ATM code so that it
<pre><code>import java.util.Scanner;
import userAccountInformation.csv;

public class AtmMachine {

 private double availableBalance;
 private double totalBalance;
 Scanner input = new Scanner(System.in);

 public int userAccount() {
  System.out.print("Please enter your account number: ");
  int account;
  account = input.nextInt();
  validateInput();
  return account;
 }

 public int userPin() {
  System.out.print("Please enter your pin number: ");
  int pin;
  pin =input.nextInt();
  validateInput();
  return pin;
 }

public void startAtm() {
 userAccount();
 userPin();
 drawMainMenu();
}

public void drawMainMenu() {
 int selection;

 System.out.println("\nATM main menu:");
 System.out.println("1 - View account balance");
 System.out.println("2 - Withdraw funds");
 System.out.println("3 - Add funds");
 System.out.println("4 - Terminate transaction");
 System.out.print("Choice: ");
 selection =input.nextInt();

 switch(selection) {

 case 1:
 viewAccountInfo();
 break;
 case 2:
 withdraw();
 break;
 case 3:
 addFunds();
 break;
 case 4:
 System.out.println("Thank you for using this ATM!!! goodbye");
 }
}

public void viewAccountInfo() {
 System.out.println("Account Information:");
 System.out.println("\t--Total balance: $"+totalBalance);
 System.out.println("\t--Available balance: $"+availableBalance);
 drawMainMenu();
}

public void deposit(int depAmount) {
 System.out.println("\n***Please insert your money now...***");
 totalBalance =totalBalance +depAmount;
 availableBalance =availableBalance +depAmount;
}

public void checkNotSufficientFunds(int withdrawAmount) {
 if(totalBalance -withdrawAmount &lt; 0)
 System.out.println("\n***ERROR!!! Insufficient funds in you accout***");
 else {
  totalBalance =totalBalance -withdrawAmount;
  availableBalance =availableBalance -withdrawAmount;
  System.out.println("\n***Please take your money now...***");
 }
}

public void addFunds() {

 int addSelection;

 System.out.println("Deposit funds:");
 System.out.println("1 - $20");
 System.out.println("2 - $40");
 System.out.println("3 - $60");
 System.out.println("4 - $100");
 System.out.println("5 - Back to main menu");
 System.out.print("Choice: ");
 addSelection =input.nextInt();

 switch(addSelection) {

 case 1:
 deposit(20);
 drawMainMenu();
 break;
 case 2:
 deposit(40);
 drawMainMenu();
 break;
 case 3:
 deposit(60);
 drawMainMenu();
 break;
 case 4:
 deposit(100);
 drawMainMenu();
 break;
 case 5:
 drawMainMenu();
 break;
 }
}

public void withdraw() {

 int withdrawSelection;

 System.out.println("Withdraw money:");
 System.out.println("1 - $20");
 System.out.println("2 - $40");
 System.out.println("3 - $60");
 System.out.println("4 - $100");
 System.out.println("5 - Back to main menu");
 System.out.print("Choice: ");
 withdrawSelection =input.nextInt();

 switch(withdrawSelection) {
 case 1:
 checkNotSufficientFunds(20);
 drawMainMenu();
 break;
 case 2:
 checkNotSufficientFunds(40);
 drawMainMenu();
 break;
 case 3:
 checkNotSufficientFunds(60);
 drawMainMenu();
 break;
 case 4:
 checkNotSufficientFunds(100);
 drawMainMenu();
 break;
 case 5:
 drawMainMenu();
 break;
 }
}

public static void main(String args[]) {

 AtmMachine myAtm = new AtmMachine();
 myAtm.startAtm();
 }
}

validateInput() {

}
</code></pre>

<p>But could someone help me write the validateInput() method so that it:
1. Checks account number and password and verify against a text file of users. Allow three tries.</p>

<p>As well as help me change it so that it:</p>

<ol>
<li>If multiple checks are being deposited, save the values in an array then update the text file.</li>
<li>Deposits, transfers, and withdrawals modify the text file.</li>
<li>If a user is NOT a customer of your bank, any withdrawals are charged an extra $2.00.</li>
<li>Balances are checked against the text file.</li>
</ol>

<p>*<em>Where I'm having problems:</em>*Incorporating a text file into the code so I can check against it and update it when needed / Writing the validateInput() method.</p>

<p>I'm assuming this will need a lot of work so any help is appreciated...</p>
