Question

Project 9-2: Account Balance Calculator

Create an application that calculates and displays the starting and ending monthly balances for a checking account and a savings account.

--->Console

Welcome to the Account application

Starting Balances

Checking: $1,000.00

Savings:  $1,000.00

Enter the transactions for the month

Withdrawal or deposit? (w/d): w

Checking or savings? (c/s): c

Amount?: 500

Continue? (y/n): y

Withdrawal or deposit? (w/d): d

Checking or savings? (c/s): s

Amount?: 200

Continue? (y/n): n

Monthly Payments and Fees

Checking fee:              $1.00

Savings interest payment:  $12.00

Final Balances

Checking: $499.00

Savings:  $1,212.00

Specifications

Create interfaces named Depositable, Withdrawable, and Balanceable that specify the methods that can be used to work with accounts. The Depositable interface should include this method:

void deposit(double amount)

The Withdrawable interface should include this method:

void withdraw(double amount)

And the Balanceable interface should include these methods:

double getBalance()
void setBalance(double amount)

Create a class named Account that implements all three of these interfaces. This class should include an instance variable for the balance.

Create a class named CheckingAccount that inherits the Account class. This class should include an instance variable for the monthly fee that's initialized to the value that's passed to the constructor. This class should also include methods that subtract the monthly fee from the account balance and return the monthly fee.

Create a class named SavingsAccount that inherits the Account class. This class should include instance variables for the monthly interest rate and the monthly interest payment. The monthly interest rate should be initialized to the value that's passed to the constructor. The monthly interest payment should be calculated by a method that applies the payment to the account balance. This class should also include a method that returns the monthly interest payment.

Create a class named AccountBalanceApp that uses these objects to process and display deposits and withdrawals.

Use the Console class presented in book Murach's Java programming 5 the edition in chapter 7 or an enhanced version of it to get and validate the user's entries. Don't allow the user to withdraw more than the current balance of an account.

Answer 1

Code:

1) Withdrawable.java

package savingsaccountcurrentaccount;

public interface Withdrawable {
  
/**
* Withdraw.
*
* @param amount the amount
*/
void withdraw(double amount);
}

2) Depositable.java

package savingsaccountcurrentaccount;

public interface Depositable {
  
/**
* Deposit.
*
* @param amount the amount
*/
void deposit(double amount);
}

3) Balancable.java

package savingsaccountcurrentaccount;

public interface Balanceable {
double getBalance();
  
/**
* Sets the balance.
*
* @param amount the new balance
*/
void setBalance(double amount);
}

4) Account.java

/**
*
*/
package savingsaccountcurrentaccount;

/**
* @author PC
*
*/
public class Account implements Depositable, Withdrawable, Balanceable {

private double balance;
  
  
/**
* default constructor
*/
public Account() {
super();
}

/*
* (non-Javadoc)
*
* @see savingsaccountcurrentaccount.Balanceable#getBalance()
*/
@Override
public double getBalance() {
return balance;
}

/*
* (non-Javadoc)
*
* @see savingsaccountcurrentaccount.Balanceable#setBalance(double)
*/
@Override
public void setBalance(double amount) {
if (amount > 0)
this.balance = amount;
}

/*
* (non-Javadoc)
*
* @see savingsaccountcurrentaccount.Withdrawable#withdraw(double)
*/
@Override
public void withdraw(double amount) {
if (amount > 0 && this.balance - amount > 0)
this.balance = this.balance - amount;
else {
System.out.println("Unable to withdraw, insufficient funds..");
}

}

/*
* (non-Javadoc)
*
* @see savingsaccountcurrentaccount.Depositable#deposit(double)
*/
@Override
public void deposit(double amount) {
if (amount > 0)
setBalance(this.balance + amount);
}

}

5) SavingsAccount.java

/**
*
*/
package savingsaccountcurrentaccount;

/**
* @author PC
*
*/
public class SavingsAccount extends Account {
private double monthlyIntrestRate;
private double monthlyIntrestPayment;
  
/**
*
* @param monthlyIntrestRate
*/
public SavingsAccount(double monthlyIntrestRate) {
super();
this.monthlyIntrestRate = monthlyIntrestRate;
}
  
/*
* returns monthly interest payment
*/
public double getMonthlyInterestPayment(){
return monthlyIntrestPayment;
}
  
/*
* calculates and sets the monthly interest payment
*/
private void setMonthlyInterestPayment(){
monthlyIntrestPayment = getBalance() * monthlyIntrestRate;
}
  
/*
* adds interest to balance
*/
public void addMonthlyInterest(){
setMonthlyInterestPayment();
setBalance(getBalance()+ monthlyIntrestPayment);
}
  
  

}

6) CheckingAccount.java

/**
*
*/
package savingsaccountcurrentaccount;

/**
* @author PC
*
*/
public class CheckingAccount extends Account {
private double monthlyFee;

/**
* @param monthlyFee
*/
public CheckingAccount(double monthlyFee) {
super();
this.monthlyFee = monthlyFee;
}
  
/*
* Deduces monthly charges from balance
*/
public void chargeMonthlyFee(){
setBalance(getBalance()- monthlyFee);
}

/**
* @return the monthlyFee
*/
public double getMonthlyFee() {
return monthlyFee;
}
  
  

}

7) AccountBalanceApp.java

/**
*
*/
package savingsaccountcurrentaccount;

import java.util.Scanner;

/**
* @author PC
*
*/
public class AccountBalanceApp {

/**
* @param args
*/
public static void main(String[] args) {
//for input
Scanner sc = new Scanner(System.in);
  
//creating objects of savings and checking accounts
SavingsAccount savings = new SavingsAccount(0.01);
CheckingAccount checking = new CheckingAccount(1);

//starting
System.out.println("Welcome to the Account Application");
char again = 'Y';
  
//asking for initial balances
System.out.println("Starting Balances");

System.out.print("Checking: $");
checking.deposit(sc.nextDouble());
System.out.print("Savings: $");
savings.deposit(sc.nextDouble());

System.out.println("Enter the transactions for the month");

//started taking monthly transactions
do {
char choice;
//taking choice
System.out.println("Withdrawal or deposit? (w/d): ");
choice = sc.next().charAt(0);
  
if (Character.toUpperCase(choice) == 'W') {//if withdrawal
  
//taking choice
System.out.println("Checking or savings? (c/s): ");
choice = sc.next().charAt(0);
  
if (Character.toUpperCase(choice) == 'C') { //for checking
System.out.println("Amount?: ");
checking.withdraw(sc.nextDouble());

} else if (Character.toUpperCase(choice) == 'S') { //for savings
System.out.println("Amount?: ");
checking.withdraw(sc.nextDouble());
  
} else { //invalid
System.out.println("Invalid ! choice ");
}

  
} else if (Character.toUpperCase(choice) == 'D') { //if deposit
//taking choice
System.out.println("Checking or savings? (c/s): ");
choice = sc.next().charAt(0);
  
if (Character.toUpperCase(choice) == 'C') { //for checking
System.out.println("Amount?: ");
checking.deposit(sc.nextDouble());

} else if (Character.toUpperCase(choice) == 'S') {//for savings
System.out.println("Amount?: ");
savings.deposit(sc.nextDouble());
  
} else { //invalid
System.out.println("Invalid ! choice ");
}

} else { //invalid
System.out.println("Invalid ! choice try again");
}
  
//taking option
System.out.println("Continue? (y/n):");
again = sc.next().charAt(0);
} while (Character.toUpperCase(again) != 'N'); //loop till enterd n/N
  
//adding monthly charges and interests
savings.addMonthlyInterest();
checking.chargeMonthlyFee();
  
//printing monthly summary
System.out.println("\nMonthly Payments and Fees");
System.out.printf("Checking fee: $%.2f\n",checking.getMonthlyFee());
System.out.printf("Savings interest payment: $%.2f\n",savings.getMonthlyInterestPayment());

System.out.println("Final Balances");
System.out.printf("Checking: $%.2f\n",checking.getBalance());
System.out.printf("Savings: $%.2f\n",savings.getBalance());
  
sc.close();
}

}

Output Screenshot: