Question

9.7 (The Account class) Design a class named Account that contains: • A private int data field named id for the account (default o). • A private double data field named balance for the account (default o). • A private double data field named annualInterestRate that stores the current interest rate (default o). Assume that 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 account. • A method named deposit that deposits a specified amount to the account. Draw the UML diagram for the class 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 annualInterestRate is a percentage, for example 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.

Answer 1

SOURCE CODE IN JAVA:

Account.java

import java.util.Date;

class Account

{

//instance variables, different for every Account

private int id;

private double balance;

private Date dateCreated;

//class variable, same for all Accounts

private static double annualInterestRate=0;

//no-arg constructor

public Account()

{

    id=0;

    balance=0;

    dateCreated=new Date();

}

//parametrized constructor

public Account(int id, int balance)

{

    this.id=id;

    this.balance=balance;

    dateCreated=new Date();

}

//accessor methods

public int getId()

{

    return id;

}

public double getBalance()

{

    return balance;

}

public Date getDateCreated()

{

    return dateCreated;

}

public static double getAnnualInterestRate()

{

    return annualInterestRate;

}

//mutator methods

public void setId(int id)

{

    this.id=id;

}

public void setBalance(double balance)

{

    this.balance=balance;

}

public static void setAnnualInterestRate(double annualInterestRate)

{

    Account.annualInterestRate=annualInterestRate;

}

//method to return monthly interest rate

public static double getMonthlyInterestRate()

{

    return annualInterestRate/12;

}

//method to return monthly interest for an Account

public double getMonthlyInterest()

{

    return (getMonthlyInterestRate()/100)*balance;

}

//method to withdraw from balance

public void withdraw(double amount)

{

    if(amount<=balance)

    balance-=amount;

}

//method to deposit into balance

public void deposit(double amount)

{

    balance+=amount;

}

}

Main.java

class Main

{

public static void main(String[] args)

{

    //testing class Account

    Account ac=new Account(1122, 20000);

    Account.setAnnualInterestRate(4.5);

    ac.withdraw(2500);

    ac.deposit(3000);

    System.out.printf("The balance is $%.2f\n", ac.getBalance());

    System.out.printf("The monthly interest is $%.2f\n", ac.getMonthlyInterest());

    System.out.println("Date of creation: "+ac.getDateCreated());

}

}

OUTPUT:

The balance is $20500.00 The monthly interest is $76.88 Date of creation: Mon Apr 20 13:32:52 UTC 2020

Regards!