L06 - Bank Account Lab

In this lab, we'll implement three classes: BankAccount, CheckingAccount, and BankAccountTest. As we write these classes, we will be taking advantage of Java's inheritance and polymorphism capabilities to make our job easier.

BankAccount Class

This is the parent class. The CheckingAccount will be derived from this class.

Member variables

double balance

Constructors

public BankAccount()

• creates a BankAccount with a zero balance

public BankAccount(double initialBalance)

• creates a BankAccount with a value of initial balance

Methods

public void deposit(double amount)

• increases the balance by amount

public void withdraw(double amount)

• decreases the balance by amount

public double getBalance()

• returns the current balance

BankAccount.java

Download this file from Drive, it’s in L06F.zip and fill in the blanks with the missing code.

/**
Parent BankAccount class 
@author __________ 
@version __________
*/
public class BankAccount { 
  __________ double balance;
   
  public BankAccount(){ 
    balance = 0; 
  } 
  
  public BankAccount(double initialBalance) { 
    balance = __________; 
  }
   
  public __________ deposit(double amount) { 
    balance = __________ + amount; 
  } 
  
  
  public void withdraw(double amount) { 
    balance = __________ - amount; 
  } 
  
  public double getBalance() {
    return __________;
  }
}

CheckingAccount Class

This class extends the BankAccount class.

Member variables

int transactionCount

• the number of transactions accumulated over a month

Constructors

public CheckingAccount()

• creates a checking account with a zero balance and sets transactionCount to zero.

public CheckingAccount(double initialBalance)

• creates a checking account and with a balance of initialBalance and sets transactionCount to zero.

Methods

public void deposit(double amount)

• increases the balance by amount and increases the transactionCount by 1.

public void withdraw(double amount)

• decreases the balance by amount and increases the transactionCount by 1.

public void deductFees()

• deducts the accumulated transaction fees and resets the transactionCount to 0. If there are more than three transactions, then the fee is equal to 2.00*(transactionCount – 3). Note that the first three transactions are free and that the fee per transaction is $2.00.

CheckingAccount.java

Download this file from Drive, it’s in L06F.zip and fill in the blanks with the missing code.

/**
Child CheckingAccount class
@author __________
@version __________
*/
public class CheckingAccount __________ BankAccount { 
  __________ int transactionCount; 
  
  public CheckingAccount() { 
    transactionCount = 0; 
  } 
  
  public CheckingAccount(double initialBalance) { 
    super(__________); 
    //use the super class constructor that's already coded 
    transactionCount = 0; 
  } 
  
  public __________ deposit(double amount) { 
    super.deposit(amount); 
    transactionCount = __________ + 1; 
  } 
  
  public void withdraw(double amount) { 
    __________.withdraw(amount); 
    transactionCount = __________ + 1; 
  }
  
  public void deductFees() { 
    if (transactionCount > 3) { 
      double fee = 2.0*(transactionCount – 3); 
      __________.withdraw(fee); 
    } 
    transactionCount = 0; 
  } 
} 

Testing Our Classes

To test our two classes, we'll write a BankAccountTest class that performs the following:

• Instantiates a checking account with an initial balance specified by the user
• Presents a menu with the following options:
  • D - Deposit money into the checking account (prompt the user for amount)
  • W - Withdraw money from the checking account (prompt user for amount)
  • P - Process end-of-month activities (withdraw fees for the checking account)
  • S - Show the current checking account balance
  • E - Exit the program

BankAccountTest.java

Download this file from Drive, it’s in L06F.zip and fill in the blanks with the missing code.

import java.util.*;
/**
BankAccount test class 
@author __________
@version __________
*/
public class BankAccountTest { 
  public static void main(String[] args) { 
    Scanner myScanner = new Scanner(System.in); 
    System.out.print("Enter initial checking account balance: ");
    double amount = Double.parseDouble(myScanner.nextLine());
    CheckingAccount myChecking = new CheckingAccount(amount);
     
    System.out.println("D - Deposit into checking");
    System.out.println("W - Withdraw from checking");
    System.out.println("P - End of month processing");
    System.out.println("S - Show account balance");
    System.out.println("E - Exit the program"); 
    
    boolean done = false; 
    
    while (!done) {
      System.out.print("> "); 
      String choice = myScanner.nextLine(); 
      
      if (choice.equalsIgnoreCase("D")) {
        System.out.print("Enter amount to deposit: "); 
        amount = Double.parseDouble(myScanner.nextLine());
        myChecking.deposit(amount); 
      }
      else if (choice.equalsIgnoreCase("W")) { 
        System.out.print("Enter amount to withdraw: "); 
        amount = Double.parseDouble(myScanner.nextLine());
        myChecking.withdraw(amount); 
      } 
      else if (choice.equalsIgnoreCase("P")) 
        myChecking.deductFees(); 
      else if (choice.equalsIgnoreCase("S"))
        System.out.println("Checking balance: " + myChecking.getBalance()); 
      else if (choice.equalsIgnoreCase("E")) 
        done = true; 
      else 
        System.out.println("Invalid menu choice - please re-enter"); 
    }
      
    System.out.println("Goodbye!"); 
  } 
}