Description
Submit only one Ruby program finally.
1. An Account comprises an id (an integer) and a balance (a floating point), and
provides the methods deposit(amount), withdraw(amount) and to_s. A Bank
comprises a number of accounts, and provides methods add_account(id),
deposit(id, amt), withdraw(id, amt) and to_s. deposit(id, amt) deposits the given
amount into the account with the given id; a similar definition applies to withdraw.
In the Bank class, the mapping from id to Account is stored in a hash table.
Implement the Bank and Account classes as described above and write a main
script that instantiates Bank, creates three accounts in this Bank object, makes a
deposit and withdrawal to each account, then prints the Bank object using to_s.
(25 marks)
2. A Transaction comprises an id (the id of the account to which it should be applied)
and a non-zero amount. If the amount is positive, it is to be deposited to the
specified account, otherwise it is interpreted as a withdrawal. Implement this class.
The file accounts.txt contains a list of account numbers, while transactions.txt
contains a list of transactions. Extend your main script to instantiate another Bank
object, read accounts.txt, create the relevant accounts in the Bank object, and then
process the transactions from transactions.txt. Finally print the Bank object.
(25 marks)
3. Add the Enumerable mixin to the Bank class, so that the each iterator yields
the accounts in the bank one by one, and accounts are compared based on their
balance. Hence extend your main script to print (1) the largest balance across all
accounts, (2) the average account balance (3) the total amount held in the bank.
(20 marks)
4. Create a Teller class. A Teller has a name, and is associated with a Bank. It can
process a transaction (delegating detailed processing to Bank), takes a fixed
number of minutes process a single transaction and keeps track of how many
transactions it has processed. Extend the Bank class to hold a number of tellers.
Your main script should now create three teller objects named Jack, Emma and
Paul, who process a transaction in 1, 2 and 3 minutes respectively. Load the bank
with accounts from accounts.txt. Read the transactions from transactions.txt into
an array, which is subsequently passed to the process_transactions_randomly/
smartly methods described below.
(a) Add a process_transactions_randomly method to Bank that takes an array of
transactions, and processes them in sequence, allocating each transaction to a
randomly chosen teller for processing.
(b) Add a process_transactions_smartly method to Bank that takes an array of
transactions, processes them in sequence and allocates them in a more intelligent
way to the tellers. The goal is to minimise the time it will take the tellers to process
the transactions, i.e. to minimise the maximum time any teller spends processing
transactions.
Perform the setup described above, then invoke process_transactions_randomly,
then print the state of each teller. Perform the setup described above again, invoke
process_transactions_smartly, then print the state of each teller.
(30 marks)
Submission
1. You submission should contain:
1.1. All the .rb files you wrote, including one called main.rb that runs the
main script for the program.
1.2. Your test cases (if any), including all_tests.rb that runs all your tests.
1.3. A file called statement.txt containing your name, student ID and a
short statement of what you achieved, e.g., “Parts 1-3 completed correctly,
Part 4 attempted but unfinished.”
