My Null pointer exception

My Null pointer exception

I am working on a simple program for my intro to Object Oriented
programing class, where I have 3 classes: Account ATM and the main/Runner
class I am experiencing a null pointer exception error in the constructor
of the ATM class when I am trying to initialize the array of Accounts
using a loop. I am new to JAVA so I don't really know what happens. here
is the code.
import java.util.Date;
public class Account {
private int account_id;
private double account_balance;
private static double annual_interest_rate;
private Date date_Created;
Account(){
account_id = 0;
account_balance=0;
annual_interest_rate = 0;
date_Created = new Date();
}
Account(int account_id_in, double account_balance_in, double
annual_interest_rate_in){
account_id = account_id_in;
account_balance = account_balance_in;
annual_interest_rate = annual_interest_rate_in;
date_Created = new Date();
}
int get_account_id(){
return account_id;
}
double get_account_balance(){
return account_balance;
}
double get_annual_interest_rate(){
return annual_interest_rate;
}
Date get_date_created(){
return date_Created;
}
void set_account_id(int account_id_in){
account_id = account_id_in;
}
void set_account_balance(double account_balance_in){
account_balance = account_balance_in;
}
void set_annual_interest_rate(double annual_interest_rate_in){
annual_interest_rate = annual_interest_rate_in;
}
double get_monthly_interest_rate(){
return annual_interest_rate/12;
}
double get_monthly_interest(){
return (account_balance * get_monthly_interest_rate())/100;
}
void perform_deposit(double deposit_in){
account_balance += deposit_in;
}
void perform_withdraw(double withdraw_amount){
account_balance -= withdraw_amount;
}
}
public class ATM {
private Account[] acct = new Account [10];
public ATM(){
//acct = new Account[10];
for(int i = 0; i<10 ; i++){
acct[i].set_account_id(i+1);
acct[i].set_account_balance(100); // here iam getting an error.
}
//you must set their ids to values as specified in the assignment
} //these are the teacher's comments and instructions.
public void displayMenu(){
System.out.println("ATM Menu:");
System.out.println("\tenter 1 for viewing the current balance");
System.out.println("\tenter 2 for withdrawing money");
System.out.println("\tenter 3 for for depositing money");
System.out.println("\tenter 4 for exiting the main menu");
}
public boolean checkID(int id){
for(int i = 0; i<10 ; i++){
if(acct[i].get_account_id() == id){
return true;
}
}
return false;
}
public double checkBalance(int idToSearch){
int indexOfAccountToReturn = 0;
for(int i = 0; i<10; i++){
if(acct[i].get_account_id() == idToSearch){
indexOfAccountToReturn = i;
break;
}
}
return acct[indexOfAccountToReturn].get_account_balance();
}
public void withdrawFunds(int id, double amount){
for(int i=0; i<10; i++){
if(acct[i].get_account_id() == id){
acct[i].perform_withdraw(amount);
break;
}
}
}
public void depositFunds(int id, double amount){
for(int i=0; i<10; i++){
if(acct[i].get_account_id() == id){
acct[i].perform_deposit(amount);
break;
}
}
}
}
import java.util.Scanner;
import javax.swing.JOptionPane;
public class Banking_Finance_Main {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
ATM atm = new ATM();
Scanner input = new Scanner(System.in);
do{
System.out.println("Account ID?");
int id = input.nextInt();
while(!(atm.checkID(id))){
String entry = JOptionPane.showInputDialog("Incorrect
Input");
id = Integer.parseInt(entry);
}
//prevent user to proceed without the correct id; use checkID
method and store appropriately
do{
atm.displayMenu();
System.out.println("Your choice?");
int choice = input.nextInt();
while((choice >4) || (choice <1)){
String entry = JOptionPane.showInputDialog("Incorrect Imput");
choice = Integer.parseInt(entry);
}
//prevent user to proceed without the correct choice 1-4;
if(choice==1){
System.out.println("Enter the Account id to check the balance: ");
int idToSearch = input.nextInt();
System.out.println("The balance in this ACccount is: $" +
atm.checkBalance(idToSearch));
}else if(choice==2){
System.out.println("Enter the Account id to perform withdrawal: ");
int idToSearch = input.nextInt();
System.out.println("Enter the amount to be withdrawn: ");
double amountToWithdraw = input.nextDouble();
atm.withdrawFunds(idToSearch, amountToWithdraw);
}else if(choice==3){
System.out.println("Enter the Account id to perform deposit: ");
int idToSearch = input.nextInt();
System.out.println("Enter the amount to be deposited: ");
double amountToDeposit = input.nextDouble();
atm.depositFunds(idToSearch, amountToDeposit);
}else{
break;
}
}while(true);
}while(true);
}
}
I am sorry if I am using this site inappropriately, this is my first
question here so bear with me please.