Part 2 of the banking app
I also
overrode the ToString() method that is ubiquitous in every .Net object
public override string ToString()
{
string fullDetails;
fullDetails = m_accountNumber + "," + m_firstName + "," +
lastName + "," + m_accountBalance.ToString();
return fullDetails;
}
The constructors
I created two
constructors one with parameters that takes in the account details such as
first name, last name, account number and account balance.
public BankAccount(string fName, string lName, string acNumber, decimal acBalance)
{
//initialize the account when the object is created
m_firstName = fName;
m_lastName = lName;
m_accountNumber = acNumber;
m_accountBalance = acBalance;
}
The second was a parameter-less constructor that allows List of bank account
(List<BankAccount> AccountsList = new List<BankAccount>();)
to be created on the winform that consumes the
bank account class (covered later)
public BankAccount()
{
//parameterless constructor
}
Getting carried away
Naturally you
would want to record all the transactions occurring on the account class that
is all the deposits and withdrawals and account opening transaction
The Transaction class
The class
would have three members(state): Transaction Type, Transaction Amount and
Timestamp
private TransactionType m_transType;
private decimal m_transAmount;
private string m_timestamp;
The
transaction type is an enum that allows you to enumerate the kind of
transaction being carried out
public enum TransactionType
{
Deposit=1,
Withdrawal,
OpeningBalance
}
Property methods
public string Timestamp
{
get { return m_timestamp; }
set { m_timestamp = value; }
}
public TransactionType TransType
{
get { return m_transType; }
set { m_transType = value; }
}
public decimal TransactionAmount
{
get { return m_transAmount; }
set { m_transAmount = value; }
}
The
m_transAmount is the amount transacted, the m_timestamp is the date and time of
transaction. Pretty simple huh?
Methods
Not many
methods although this can be enhanced in the remote chance that this becomes a
more complex app
Overriding the ToString()
method
Very useful
when you want to return the state of the object in a string format
public override string ToString()
{
string res = "";
res = m_timestamp + ": " + m_transType.ToString() + " -: " + m_transAmount.ToString();
return res;
}
And finally
the constructor – Parameter – less because
we want to be able to create a List<Transaction>( a list of transactions
in each bank account class)
public Transaction()
{
//parameterless constructor
}
So the whole
Transaction class would look like this
public class Transaction
{
public Transaction()
{
//parameterless constructor
}
public override string ToString()
{
string res = "";
res = m_timestamp + ": " + m_transType.ToString() + " -: " + m_transAmount.ToString();
return res;
}
public enum TransactionType
{
Deposit=1,
Withdrawal,
OpeningBalance
}
private TransactionType m_transType;
private decimal m_transAmount;
private string m_timestamp;
public string Timestamp
{
get { return m_timestamp; }
set { m_timestamp = value; }
}
public TransactionType TransType
{
get { return m_transType; }
set { m_transType = value; }
}
public decimal TransactionAmount
{
get { return m_transAmount; }
set { m_transAmount = value; }
}
}
}
Now Going
back to the Account class we enhance the class be declaring the list of
transactions List<Transaction> as a member like so
private List <Transaction> m_transactions=new List<Transaction>();
Then add a
property method to return a list of transactions for each BankAccount object
created. Like so
public List<Transaction> Transactions
{
get { return m_transactions;}
}
We then
enhance the Constructor, WithDraw and Deposit Methods in order to record a
transaction each time the user transacts
The enhanced constructor
public BankAccount(string fName, string lName, string acNumber, decimal acBalance)
{
//initialize the account when the object is created
m_firstName = fName;
m_lastName = lName;
m_accountNumber = acNumber;
m_accountBalance = acBalance;
Transaction trans = new Transaction();
trans.TransType = Transaction.TransactionType.OpeningBalance;
trans.Timestamp = DateTime.UtcNow.ToString();
trans.TransactionAmount = acBalance;
m_transactions.Add(trans);
}
Because
opening an account is essentially a transaction type of OpeningBalance we
create a transaction object, give it the AcBalance as the transaction amount,
the timestamp now and we mark the transaction as OpeningBalance. We then add
the transaction into the list of transactions of the account
m_transactions.Add(trans);
The WithDrawMethod
public decimal WithDraw(decimal withdrawalAmount)
{
Transaction trans = new Transaction();
trans.TransType = Transaction.TransactionType.Withdrawal;
trans.TransactionAmount = withdrawalAmount;
trans.Timestamp = DateTime.UtcNow.ToString();
m_transactions.Add(trans);
m_accountBalance -= withdrawalAmount;
return accountBalance;
}
As we have
done in the constructor we enhance the WithDraw method by declaring a
transaction object, the transaction type is Withdrawal, the TransactionAmount
is withdrawalAmount and the time of transaction is the time stamp
The DepositMethod
public decimal Deposit(decimal depositAmount)
{
Transaction trans = new Transaction();
trans.TransType = Transaction.TransactionType.Deposit;
trans.TransactionAmount = depositAmount;
trans.Timestamp = DateTime.UtcNow.ToString();
m_transactions.Add(trans);
m_accountBalance += depositAmount;
return accountBalance;
}
The transaction
type is Deposit
The Enhanced ToString() Method
We want the
ToString() method to list the state of the object i.e. The account number,
first name, last name, account balance as well as list the transactions carried
out on the BankAccount
public override string ToString()
{
string fullDetails;
fullDetails = m_accountNumber + "," + m_firstName + "," +
lastName + "," + m_accountBalance.ToString();
foreach(Transaction trans in m_transactions)
{
fullDetails += "\n --" + trans.ToString();
}
return fullDetails;
}
So we loop through
the m_transactions member and use the trans.ToString method to return the
object state as a string. We then concatenate
it with the BankAccount state. Very nifty no?
Part 3 Follows
Part 3 Follows
