/**
* Class BankAccount - a simple model of a bank account
* designed to illustrate the concepts of classes, objects, and methods.
*
* @author Man Hin Wong
*
* @version 2010.08.12-version
*/
class BankAccount
{
// These are the instance variables
private int balance;
private String accountName;
// TODO Add new instance variables here
private int valueDeposits;
private int valueWithdrawals;
private int maximumBalance;
private int minimumBalance;
// This is the constructor
public BankAccount(String accountName, int balance) {
this.accountName = accountName;
this.balance = balance;
// TODO Initialise all new instance variables
this.valueDeposits = 1000;
this.valueWithdrawals = 0;
this.maximumBalance = balance;
this.minimumBalance = balance;
}
// Prescribed accessor methods
public int getBalance() {
return balance;
}
public String getAccountName() {
return accountName;
}
// TODO Methods that need updating
public void deposit(int amount) {
balance = balance + amount;
valueDeposits = valueDeposits + amount;
if (maximumBalance<balance) {
maximumBalance=balance;
}
// TODO Handle instance variables that change on deposit
}
public void withdraw(int amount) {
balance = balance - amount;
valueWithdrawals = valueWithdrawals + amount;
if (minimumBalance>balance) {
minimumBalance=balance;
}
// TODO Handle instance variables that change on withdrawal
}
public int getValueDeposits() {
// TODO Complete this accessor method and return correct value
return valueDeposits;
}
public int getValueWithdrawals() {
// TODO Complete this accessor method and return correct value
return valueWithdrawals;
}
public boolean isOverdrawn() {
// TODO Complete this accessor method and return correct value
if (balance<0) {
return true;}
else
{
return false;} // always fail
}
// TODO Add additional accessor methods here (there are two)
public int getMaximumBalance() {
return maximumBalance;
}
public int getMinimumBalance() {
return minimumBalance;
}
// TODO Add additional method here (there is one)
public void applyInterest(double rate) {
if (valueWithdrawals>balance) {
interest = (int) (balance*double rate);
}
}
}
Instruction:
This method credits interest to an account provided it is not overdrawn and depends on the parameter rate which is of type double (thus an interest rate of 5% is represented as 0.05). The interest rate will always be positive (> 0). Overdrawn accounts remain unaffected by this method. For example, if the call applyInterest(0.0325) is made and the account has a current balance of 1055, the new balance should be 1089.
Note that multiplying an int by a double gives a double result: in order to assign this to an int variable, you need to cast the result to an int.
int interest;
int balance = 159;
double rate = 0.05;
interest = balance*rate; // This will not compile because balance*rate (=7.95) is a double
// (extended decimal) and interest is an int (integer)
interest = (int) (balance*rate); // This will work and be equal to 7 (a truncation of 7.95).
Don't forget the side effects of depositing interest: adding interest counts as a deposit for the purpose of computing the total value of all deposits and may change the historical maximumBalance.
I don't know what's going on here.
I can't fix this and I have to hand in my work soon!!
