cHILL ‘em All

For the Customer class:

First thing to do, you need to create the class.
For the Ticket Machine last week, creation of the class was done and
is always done by:

public class TicketMachine{

}

Everything goes inside the CLASS braces ( the { and } ). All other
methods, declorations, everything. They are the first and last braces
in the java file.

Mairead calls the Class the blueprint, but she never mentioned it is
the blueprint for each specific physical thing. Like a Customer, a
TicketMachine, a Car.
All classes start with a capital letter.

Right, the fields.
Fields store values.
If the field type is an int, a ‘char’, a “String”; that means they
hold integers, single characters, or a String of characters( ie a
sentince).

- Creating a field
If i wanted to create a field for the Customer class that held, for
example, someone’s favourite colour,
you would create a String type and name it something that made it
kinda obvious like favColour.
Note: you don’t have to, but it’s good to name them all in small
letters, until the start if a new word, then that in a cap, so if i
wanted to make a String called: When in Dome, I would write:

private String whenInDome;

What this actually does it it creates a space in the computers memory
called whenInDome, and says; “Right, this can only hold “String” ’s.

Imagine every field you create as a cardboard box, if you create, for example:

private int waa;

Then a cardboard box is set aside, its contents can only be ints, and
it’s got “waa” written on it because that is what it is now referred
to as.

So we’ve got our cardboard boxes set aside but there’s nothing in them
right now.

//======================

Going back to Customer.class

for the assignment, we need to create 3 of these ‘cardboard boxes’,
one that holds someone’s name, one that holds someone’s address
address,
and one that holds someone’s overdraft limit.

She even tells us what type we want, ie – as in the pdf,
String name, String address, and double overdraftLimit.

(double is similar to int, it just holds decimal points, you need that
for bank acc’s)

look up at the whenInDome and waa examples and make name, address and
overdraftLimit your self! fuckers..

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Constructors

Right, when you create a class for the first time, everything that’s
(any assignments or anything, ill go into more detail)
in the constructor is what happens initially, if you didnt have a
constructor, nothing would happen when you created the class.

In the TicketMachine example, the constructor was something like:

public TicketMachine( )
{
total = 0;
balance = 0;
numCoins = 0;
}

what this did was take the value 0, and put it into our carboard box
called total that only stores ints.
it then puts the value 0, and puts in into the cardboard box called
balance that only stores ints, and ditto for numCoins.
THIS IS NOT THE NAME AS HAVING THE BOX EMPTY.

there is another thing about the contstructor. Lets say you didnt want
to set the initial balance to 0, you wanted that everytime you created
the class,
that you wanted to define what total, balance, and numCoins were. it
would look like this:

public TicketMachine(int newTotal, int newBalance, int newNumCoins)
{
total = newTotal;
balance = newBalance;
numCoins = newNumCoins;
}

in this example, the first line: public TicketMachine(int newTotal,
int newBalance, int newNumCoins)

this tells the compiler, (the thing that checks all your code to see
how wrong it is) that for TicketMachine, there are 3 parameters,
the first is an int, the second is an int, and the third is an int.

the actual names of the parameters mean nothing, but I always name
them newX, where X is the current thing they will be replacing. (eg
total and newTotal).

—Bringing this back to Customer, she wants you to set the name,
address, and overdraft limit.
I’m refusing to give out the actual code coz you wont learn shit,
but it’s not too bad when you think about it;

Substitute the names of the classes: Customer is the name we want,
TicketMachine was last week.
We have 3 variables (anything which value can be changed, ie vary)
that are in Customer, and these defined in the parameters( the ( )’s )
again,
and as she told us in the PDF she wants them to be.

They want to be the 3 things from our cardboard boxes that we created
earlier, the String type which is called name, the String type which
is called address,
and double (which holds a number with 2 decimal points) type called
overdraftLimit.

So going by this logic,

(as in the TicketMachine) int newTotal took in an int that we wanted
to call the ‘new total’ because it was to replace total by new total.
So here, we want to do the same, for all 3.

So here, we create Customer, like we created TicketMachine above, we
take in 3 parameters, like we did above,
and we must assign the values we took in, to the ‘cardboard boxes’ we
created earlier. something like “total = newTotal”.

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