Php
Instance variables
p72 Instace variables: things the object knows (title, artist) Methods: things the object does (setTitle(), setArtist(), play()).
RunCode
class LearningApp {
public static void main(String[] args) {
Dog d = new Dog();
d.size = 40;
d.bark();
}
}
class Dog {
int size;
String name;
void bark() {
System.out.println("Ham Ham"); // Ham Ham
}
}
JVM
p74 ! You start by declare a reference variable - Doq myDog. This tells the JVM to allocate space for a reference variable. This tells the JVM to name variable - myDog. The reference variable is forever of type Dog!
Dog d = new Dog(); // links the object and the reference.
Reference
p77 In this example, we have two Book reference variables and two Book objects. RunCode
class LearningApp {
public static void main(String[] args) {
// Step 1
Book b = new Book(1); // object 1
Book c = new Book(2); // object 2
System.out.printf("%s %s \n", b.x, c.x); // 1 2
// Step 2
Book d = c; // object 3
System.out.printf("%s %s %s \n", b.x, c.x, d.x); // 1 2 2
// Step 3
c = b; // overwrite c
// c is now reference to object 1
// c reference to object 2 is destroyed
// (eligible for Garbage Collection)
System.out.printf("%s %s %s \n", b.x, c.x, d.x); // 1 1 2
}
}
class Book {
int x = 0;
public Book(int x) { // contructor
this.x = x;
}
}
... 23 lines˄˄˄ CompleteTask
/**
* Create a new Dog instance ...
* Make the dog size = 10
* Output dog size on the screen
*/
class LearningApp {
public static void main(String[] args) {
...
}
}
class Dog {
public int size;
public String name;
}
➥ Questions
CARD
02
