A bank account system

The problem

Build a program that manages several kinds of bank account, with deposits, withdrawals, transfers, monthly interest and a statement for each account.

An abstract Account class keeps the owner, the balance and a list of transactions, all private
Savings accounts earn monthly interest, and current accounts allow an overdraft up to a limit
Every rule that is broken, such as a negative amount or too little money, throws an exception of your own type
A Bank class owns all the accounts, finds them by number, and cannot be copied
operator<< prints an account's statement
All memory is released when the program ends

Write the abstract Account class with deposit, a pure virtual withdraw rule, and a transaction list.
Write SavingsAccount and CurrentAccount, each with its own withdrawal rule and monthly update.
Write the exception classes, deriving them from runtime_error, and throw them from the accounts.
Write Bank, which owns Account pointers in a map from account number, deletes them in its destructor, and forbids copying.
Add transfers between accounts, making sure a failed withdrawal leaves both balances unchanged.
Write operator<< for statements, and a small command loop to drive the bank.
Test overdrafts, transfers to a missing account, and many months of interest.

A working bank system where each kind of account follows its own rules and every error is reported clearly.

No balance can be changed except through the account's own member functions
Each kind of account behaves correctly, and adding a new kind needs no change to Bank
Every error is reported by an exception and leaves the data unchanged
Nothing is leaked or deleted twice