4003CEM-classes

lab_ai3

Add one line of code to the end of lab_ai3.cpp that causes secondAI to also say_hello.

lab_yourturn

Open aiyourturn.h. This starts off as a copy of the class from ai6.h. Edit this class to:

• Add a new class attribute called usedNames. This should be an empty vector of strings declared just before the constructor (AI()) (method definition.
• Add to the constructor method the code need to add the new randomly picked name to the vector usedNames.
• Create a new class method called who_is_here. The method does not have any input. It simply has one line to return the usedNames vector.

lab_rectangle

float get_side_1() const
{
    return side1;
}

Add this code into Rectangle.h and a second function for the other side.

lab_yourturn 2

Open aiyourturn.h. First change the object attribute name to private.

Second, add a method get_name() which simply returns the name of the object.

Third, add an object method set_name(newName) for changing the name of an existing AI object. The method should:

• Reassign newName to be an upper case version of itself.
• If newName is already in usedNames then the function should raise a ValueError because it is not possible to change to an already taken name.
• Otherwise: -- remove the original name from the usedNames class attribute; -- add newName to the usedNames list; -- and change name to the newName.

lab_bankaccount

Create a new file called BankAccount.h. Inside, define a class called BankAccount subject to the following requirements.

• Each object of the class should have the attributes name and private attribute balance. name should be a string whilst balance should be a float.

• The instantiation method should require an argument determining the customer's name. It should automatically initialise the balance to zero.

• Create a method get_balance which allows the user to obtain the balance of an account (but not edit it).

• Create two separate object methods called deposit and withdraw for editing the balance (increase and decrease respectively). Each method should take a positive number as input. Make sure that withdraw does not allow the balance to become negative!

Test your class by creating two bank accounts and making some deposits and withdrawals. When you are confident run the check below.

lab_bankaccount 2

Extend your class as follows.

• Add a static attribute number and getter function number_accounts which keeps count of how many accounts have been created

lab_bankaccount 3

• Write a method transfer which takes two bank accounts as input along with an amount. It transfers that amount from the first bank account to the second (assuming there is enough money in the first). As a hint for this function, make sure that you declare the parameter in the function header as BankAccount &other. The reasons for this will be covered in the pointers week.

lab_bankaccount 4

Modify your BankAccount class so that the number_accounts() method will return the correct number even if accounts are closed.

Advanced

There is a LOT of additional features of C++ classes that it is not possible to cover within the scope of this module.

If you are after additional areas to investigate these are some suggestions.

• Operator overloading
  • Can you modify your BankAccount class so that you can add and subtract money from it using the += and -= operators?
  • Can you make is so that bank accounts can be printed using cout? (Hint: look at the << operator).

BankAccount ba("Bob's account");
ba += 42;
ba -= 1;
// prints "Bob's account: £41.0"
std::cout << ba << std::endl;

• User defined conversion
  • Can you make it so that we can convert our bankaccount into a float?

BankAccount ba("Bob's account");
ba.deposit( 123 );

float balance = ba;
// prints 123.0
std::cout << balance << std::endl;