Array dan ArrayList

• Construct array:
new double[10]

• Store in variable of type double[]:
double[] data = new double[10]; 

• When array is created, all values are initialized depending on
array type:
• Numbers: 0 
• Boolean: false
• Object References: null

Syntax Array
double [] values = new double[10]
double[] moreValues = { 32,54,67,5,29,35};

Use brackest to acces an element
      values[i] = 29.95;


Array Lists
• ArrayList class manages a sequence of objects
• Can grow and shrink as needed
• ArrayList class supplies methods for many common tasks,
such as inserting and removing elements
• ArrayList is a generic class:
ArrayList<T>

collects objects of type parameter T:
ArrayList<String> names = new ArrayList<String>();
names.add("Emily");
names.add("Bob");
names.add("Cindy");

• size method yields number of elements


Adding Elements
To add an object to the end of the array list, use the add
method:
names.add("Emily");
names.add("Bob");
names.add("Cindy");

Syntax ArrayList
ArrayList<String> friends = new ArrayList<String>();

friends.add("Eko");
String name = friends.get(i);
friends.set(i,"Harry");




/arraylist/ArrayListTester.java


1.import java.util.ArrayList;
2 
3 /**
4 This program tests the ArrayList class.
5 */
6 public class ArrayListTester
7 {
8 public static void main(String[] args)
9 {
10 ArrayList<BankAccount> accounts = new ArrayList<BankAccount>();
11 accounts.add(new BankAccount(1001));
12 accounts.add(new BankAccount(1015));
13 accounts.add(new BankAccount(1729));
14 accounts.add(1, new BankAccount(1008));
15 accounts.remove(0);
16 
17 System.out.println("Size: " + accounts.size());
18 System.out.println("Expected: 3");
19 BankAccount first = accounts.get(0);
20 System.out.println("First account number: "
21 + first.getAccountNumber());
22 System.out.println("Expected: 1008"); 
23 BankAccount last = accounts.get(accounts.size() - 1);
24 System.out.println("Last account number: "
25 + last.getAccountNumber());
26 System.out.println("Expected: 1729");