Transcript Writing classes III

Lec 14
Writing an Instantiable Class III
Agenda
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Review of Instantiable Classes
Scope of variables
Using this to override scope issues
Lab: Creating a Car class for a video game
Recall Structure of an
Instantiable Class
class Balloon
Class Name
size
color
Instance Varbls
Balloon
inflate
getSize
getColor
setColor
pop
Methods
Constructor method
same name as class
Structure of an
Instantiable Dog Class
class Dog
Class Name
size
Instance Varbls
Dog
getSize
setSize
bark
Methods
Constructor method
same name as class
Now we'll begin ScopeThisDog Demo
• create Dog and MainApp classes
• show how scope errors can cause compile
failure
• scope of
– instance variables, parameters, and local variables
• Using keyword this to resolve scope issues
in Class definition files
Scope errors in code below
Memory Map
Dog fido = new Dog(30);
Lab14 You write a Car Class
class Car
Class Name
double speed;
int turnRate;
Instance Varbls
Car
getSpeed
getTurnRate
accelerate
turnMoreLeft
turnMoreRight
Methods
Constructor method
same name as class