Tuesday, 30 August 2016

Chapter 9 Exercise 7, Introduction to Java Programming, Tenth Edition Y. Daniel LiangY.

*9.7 (The Account class) Design a class named Account that contains:
A private int data field named id for the account (default 0 ).
A private double data field named balance for the account (default 0 ).
A private double data field named annualInterestRate that stores the cur-
rent interest rate (default 0 ). Assume all accounts have the same interest rate.
A private Date data field named dateCreated that stores the date when the
account was created.
A no-arg constructor that creates a default account.
A constructor that creates an account with the specified id and initial balance.
The accessor and mutator methods for id , balance , and annualInterestRate .
The accessor method for dateCreated .
A method named getMonthlyInterestRate() that returns the monthly
interest rate.
A method named getMonthlyInterest() that returns the monthly interest.
A method named withdraw that withdraws a specified amount from the
A method named deposit that deposits a specified amount to the account.
Draw the UML diagram for the class and then implement the class. (Hint: The
method getMonthlyInterest() is to return monthly interest, not the interest rate.
Monthly interest is balance * monthlyInterestRate . monthlyInterestRate
is annualInterestRate / 12 . Note that annualInterestRate is a percentage,
e.g., like 4.5%. You need to divide it by 100.)
Write a test program that creates an Account object with an account ID of 1122,
a balance of $20,000, and an annual interest rate of 4.5%. Use the withdraw
method to withdraw $2,500, use the deposit method to deposit $3,000, and print
the balance, the monthly interest, and the date when this account was created.

import java.util.ArrayList;
import java.util.Date;

public class Account {

    protected String mName;
    protected int mId;
    protected double mBalance;
    protected double mAnnualInterestRate; // AnnualInterestRate is percentage.
    protected Date mDateCreated;
    protected ArrayList<Transaction> mTransactions;

    public Account() {
        mDateCreated = new Date();
        mTransactions = new ArrayList<>();

    public Account(int id, double balance) {
        mId = id;
        mBalance = balance;

    public Account(String name, int id, double balance) {
        this(id, balance);
        mName = name;


    public int getId() {
        return mId;

    public void setId(int id) {
        mId = id;

    public double getBalance() {
        return mBalance;

    public void setBalance(double balance) {
        mBalance = balance;

    public double getAnnualInterestRate() {
        return mAnnualInterestRate;

    public void setAnnualInterestRate(double annualInterestRate) {
        mAnnualInterestRate = annualInterestRate;

    public Date getDateCreated() {
        return mDateCreated;

    public double getMonthlyInterestRate() {
        return mBalance * (mAnnualInterestRate / 12) / 100;

    public void withdraw(double amount) {
        mTransactions.add(new Transaction('W', amount, mBalance, "withdraw"));
        mBalance -= amount;

    public void deposit(double amount) {
        mTransactions.add(new Transaction('D', amount, mBalance, "deposit"));
        mBalance += amount;

    public String toString() {
        return "Account name: " + mName + "\n" + "Interest rate: " + mAnnualInterestRate + "\n" + mTransactions;

    public ArrayList<Transaction> getTransactions() {
        return new ArrayList<>(mTransactions);


public class Exercise_07 {

    public static void main(String[] args) {

        Account account = new Account(1122, 20000);

        System.out.println("Account ID: " + account.getId());
        System.out.println("Account Balance: " + account.getBalance());

        System.out.println("Withdrawing $2,500...");

        System.out.println("Depositing $3,000...");

        System.out.println("Displaying updated info.");
        System.out.println("Account ID: " + account.getId());
        System.out.println("Account Balance: " + account.getBalance());
        System.out.println("Monthly interest rate: " + account.getMonthlyInterestRate());
        System.out.println("Date account was created: " + account.getDateCreated());


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