1. Lec 13 Writing an Instantiable Class II

2. Agenda More class examples Adding to our Balloon Class demo:
default Constructor method
inflate method that takes a parameter (amount)
pop method
volume method

3. We have been working with objects to represent complex things (Strings, Islands, Scanners)

4. Now we are taking a look at what's inside an object

5. data
code
(methods)

6. Structure of an Instantiable Class – blueprint for objects
Class Name
class Dog
size
breed
Dog
bark
rollOver
beg
Instance Varbls
Methods
Constructor method same name as class

7. Suppose we wanted to represent a piggy bank?
Class Name
class PiggyBank
Instance Varbls
Methods
Constructor method same name as class

8. Suppose we wanted to represent a piggy bank? (solution)
Class Name
class PiggyBank
numQuarters
numDimes
PiggyBank
addQuarters
addDimes
removeQuarters
removeDimes
currentValue
Instance Varbls
Methods
Constructor method same name as class

9. Suppose we wanted to represent a hamburger? (from lab 4)
Class Name
class Hamburger
Instance Varbls
Methods
Constructor method same name as class

10. Suppose we wanted to represent a hamburger? (solution)
Class Name
class Hamburger
numPatties
numLettuce
Hamburger
addPatty
addLettuce
print
Instance Varbls
Methods
Constructor method same name as class

11. Back to Balloon Class Name Instance Varbls Methods
class Balloon
size
color
Balloon
inflate
getSize
getColor
setColor
pop
Instance Varbls
Methods
size
Color.YELLOW
Constructor method same name as class

12. Method Overloading We can add methods to Balloon with same names
as long as have different parameters
the Constructor we made in our Balloon class
A second "Default" constructor with no parameters

13. Which one is used? Balloon myBal = new Balloon(10,Color.RED);
Balloon yrBal = new Balloon();
default constructor automatically
sets size to 0
sets color to Color.WHITE

14. Now we'll begin BalloonDemo2
start with BalloonDemo from last time
add default constructor
add inflate method that takes an amount
add pop method
modify both inflate methods
add volume method
should return 0 if balloon has been popped

15. More Dairy.java make Lab13DairyFarm folder
Copy, Dairy.java file from Lab12 folder, then add
default Constructor
addCow takes a number
calcMllkProfit takes a price/gallon
calcButterProfit takes a price/pound
Create a new class Farm.java that
tests your new Dairy class by constructing a dairy farm, adding cows and printing the number of cows
And printing profit from selling milk or butter