Q$4.$ Define classes and use objects in a test program $(6$ marks$)$

Consider a banking system where each account has a balance and an account number. Define a class called

BankAccount that represents a bank account with the following UML:

Attributes descriptions:

account$\_$number: client bank account number.

balance: the current balance of the account.

last$\_$transaction$\_$type: the type of the last transaction $("$Deposit$"$ or "Withdraw"$).$ It is $"-$ by default.

last$\_$transaction$\_$amount: the amount of the last transaction.

accounts$\_$count: static variable counts the number of accounts in the bank. The default value is $0.$

total$\_$balances: static variable defines the current balances of all accounts. The default value is

$10,000,000.$

Assume your instructor has coded most of methods and attributes, but your instructor needs your help

in the following parts:

In BankAccount Class, Write the code for the constructor $[2$ pt$]$:

a$.$ BankAccount $($ account$\_$number : String, balance : double $)$ : constructor defines the account

number and the starting balance.

b$.$ This method updates all the static member variables. The accounts$\_$count should be incremented,

and the balance should be added to the total$\_$balances.