head first java chapter 4
TRANSCRIPT
Head First Java Chapter 4Tom Henricksen
Sending to a method● Arguments
● Parameters
Dog d = new Dog();
d.bark(3);
void bark (int numOfBarks) {
Method returns● Void - void go() {...
● Value - int calculate score() { …
● Compiler
Let’s code
Dog
DogTestDrive
Pass by valueInt x = 7;
Void go(int z) {
Copy x into z
Reference Variables● Pass one or more parameters
● Match parameters
● Promote type
● Pass literal or variables
Encapsulation● Direct Access
● Use methods instead
dog.size = 50;
dog.setSize(50);
GoodDogprivate int size;
public getSize() { return size;}
public setSize(int s) { size = s; }
int x = 3 + dog.getSize();
Object ArraysDog[] pets = new Dog[7];
pets[0].setSize(30);
Instance and local variables● Instance variables
○ private int a;
○ private String name = “Dog”;
● Local variables
○ int s = 0;
Comparisons● Primitives
○ byte a = 0; byte b = 0;
○ a == b;
● Object
○ dogA.equals(dogB); dogA == dogB;
Sharpen your pencil
Which method calls work?
Be the compiler
● Exercise B