CSIS 110 – Lecture 10
Homework
Due Sept 26. Show students my version.
Ask if there are any questions?
Coding Standard!
Reading: Chapter 4: 4.1 through 4.8 (you can skip 4.7.2 and 4.7.3)
Last time: Collections
What’s a collection?
- A group of variables that can be referenced using a single name
ArrayList
- A collection provided in the Java library
- We can create an ArrayList object, and then use its methods to insert and
access elements.
- Need to tell Java where it is – use import statement
Instance Variable in class Notebook:
ArrayList<String> notes;
Create a new ArrayList object in the constructor:
notes = new ArrayList<String>();
Remind students that this is written using Java 1.5 – slightly different than the book,
which uses Java 1.4.
Some ArrayList methods:
add – store an object in the list
size – return the number of objects in the list
get – get an object from the list (but don’t remove it)
Ask students how to invoke methods on the above object (notes).
Properties of ArrayLists:
Variable size – an ArrayList gets bigger if necessary as we add more items
It keeps track of the number of items it currently contains
