[code]import java.util.Scanner;

class ATM {


    public static void main(String[] args) {
        //Declare and/or initialize variables used throughout
        int clear;
        int x = -1;
        int loop = 1;
        int menuChoice = 0;
        int arrayCount = 0;
        String loginID = null;
        user[] userArray = new user[10];
        Scanner scanner = new Scanner(System.in);

        //Menu loop
        while (loop != 0) {

            //Printed menu for user
            System.out.println("Please make a selection: ");
            System.out.println("1 - Register");
            System.out.println("2 - Login");
            System.out.println("3 - Deposit");
            System.out.println("4 - Withdraw");
            System.out.println("5 - Check Balance");
            System.out.println("6 - Log Out");

            //Menu prompt for user input
            System.out.print("Make your selection (1-6): ");
            menuChoice = scanner.nextInt();

            //Register
            if (menuChoice == 1) {

                //Conditional to check for space in array
                if (arrayCount < 10) {
                    //Creates new user obj, increments array position for next, reads user input for id, pin
                    userArray[arrayCount] = new user();
                    System.out.println("Please input your user ID:");
                    userArray[arrayCount].id = scanner.next();
                    System.out.println("Please input 4 digit PIN: ");
                    userArray[arrayCount].pin = scanner.nextInt();

                    //arrayCount incrementer to keep track of # of users
                    arrayCount++;
                }
                //Warning of full user array
                else {
                    System.out.println("Too many users!");
                }
            }

            //Login
            else if (menuChoice == 2) {

                //Clears all loginTokens
                clear = 0;
                while (clear < arrayCount) {
                    userArray[clear].loginToken = false;
                    clear++;
                }

                //User input for login, and PIN
                System.out.println("Please input your user ID (case insensitive): ");
                loginID = scanner.next();
                System.out.println("Please input your PIN: ");
                int loginPin = scanner.nextInt();

                // Uses user input to check id string input versus stored user id to find the
                //array position of the user
                x = checkID(arrayCount, loginID, userArray);

                // Checks the input PIN against the pin in stored instance variable in the
                // same array position as the id found in checkID
                userArray[x].loginToken = checkPin(x, loginPin, userArray);

            }

            //Deposit
            else if (menuChoice == 3) {

                //Retrieving array position of user
                x = checkID(arrayCount, loginID, userArray);

                if (x == -1 || userArray[x].loginToken == false) {
                    System.out.println("Please login.");
                }
                if (x > -1 && userArray[x].loginToken == true) {
                    System.out.print("How much would you like to deposit?:  ");
                    int deposit = scanner.nextInt();
                    userArray[x].balance = userArray[x].balance + deposit;
                    System.out.println("Your new balance is: $" + deposit);
                }

            }

            //Withdraw
            else if (menuChoice == 4) {
                if (x == -1 || userArray[x].loginToken == false) {
                    System.out.println("Please login.");
                }
                if (x > -1 && userArray[x].loginToken == true) {
                    System.out.print("How much would you like to withdraw?:  ");
                    int withdraw = scanner.nextInt();
                    if (withdraw < userArray[x].balance) {
                        userArray[x].balance = userArray[x].balance - withdraw;
                        System.out.println("Your new balance is $" + userArray[x].balance);
                    }
                    if (withdraw > userArray[x].balance) {
                        System.out.println("You have insufficient funds.");
                    }

                }
            }

            //Check Balance
            else if(menuChoice==5){
                if (x == -1 || userArray[x].loginToken == false) {
                    System.out.println("Please login.");
                }
                if (x > -1 && userArray[x].loginToken == true) {
                    System.out.println("Your balance is: $"+ userArray[x].balance);
                }
            }

            //Log Out
            else if (menuChoice==6) {
                //Clears all loginTokens
                clear = 0;
                while (clear < arrayCount) {
                    userArray[clear].loginToken = false;
                    clear++;
                }
            }

            //Catches invalid entries at the menu
            else {
                System.out.println("Please make a valid selection!");

            }

        }
    }


//Uses temporary variable idTemp to find array position of login credentials, if available.

static int checkID(int arrayCount, String idTemp, user[] userArray){

    int x = 0;
    //Loops through all user objects to find match
    while(x < arrayCount) {
         if(userArray[x].id.equals(idTemp)) {
             return x;
         }
         if(idTemp != userArray[x].id){
             x++;
         }
    }
    if(x==userArray.length){
        System.out.println("User was not found!");
    }
     return x;
}

//Accepts the int return of checkID to compare user input pin against the stored pin at that array position.
static boolean checkPin(int x, int inputPin, user[] userArray) {
    boolean pinBool = false;
    if(userArray[x].pin == inputPin){
        System.out.println("User " + userArray[x].id + " has been successfully logged in!");
        pinBool = true;
    }
    else{
        System.out.println("There was an error!");
    }
    return pinBool;
}



}

//User object
class user{
       String id;
       int pin;
       int balance;
       boolean loginToken = false;
    };
[/code]