bank.rb

class NotEnoughCashError < Exception
end

class Bank
    attr_reader :accounts
    attr_reader :name

    def initialize(name)
        @name = name
        @accounts = []
    end

    def add_accounts(accounts)
        @accounts.concat(accounts)
    end

    def num_chequing_accounts
        @accounts.select { |acc| acc.class.name=="ChequingAccount" }.length
    end

    def transfer(from_account, to_account, amount)
        begin
            from_account.withdraw(amount)
            to_account.deposit(amount)
        rescue NotEnoughCashError => e
            puts e
        end
    end
end

class Account
    attr_accessor :owner, :balance

    def initialize(owner, balance)
        @owner = owner
        @balance = balance
    end

    # instance or class?
    def self.create_accounts(owner)
        s = SavingsAccount.new(owner, 0)
        c = ChequingAccount.new(owner, 0)

        [s, c]
    end
    def withdraw(amount)
        self.balance -= amount
    end
    def deposit(amount)
        self.balance += amount
    end
end

class SavingsAccount < Account
    @@num_savings_accounts = 0

    def initialize(name, balance)
        super
        @@num_savings_accounts += 1
    end
end

class ChequingAccount < Account
    @@num_chequing_accounts = 0

    def initialize(name, balance)
        super
        @@num_chequing_accounts += 1
    end

    # instance method
    def withdraw(amount)
        if self.balance - amount < 50
            raise NotEnoughCashError, "Chequing Accounts must have at least $50 at all times"
        else
            self.balance -= amount
        end
    end
end


bank = Bank.new("Bank of Rob Ford")

accounts = Account.create_accounts("murat")
bank.add_accounts(accounts)

account = ChequingAccount.new("me", 0)
account2 = SavingsAccount.new("not mee", 200)

bank.transfer(account, account2, 50)

# assigning to a new variable name  does not change memory address
account3 = account

puts "arrived at end of file"

exceptions.rb

def something(arg1, arg2)
end

begin
    something("just one arg")
    456/0 # ZeroDivisionError
    lol   # NameError
rescue ZeroDivisionError => e
    puts "tried dividing by zero"
rescue NameError => e
    puts "gracefully handling error"
    puts e
rescue Exception => e # catchall
    puts "caught generic exception"
    puts e
end
    
puts "reached end of file"