CSIS 110 – Lecture 9
Quiz Results (Before EC)
mean 19.6
stdev 3.9
median 18.5
max 25
Distribution (after EC):
<15: 1 15-17: 4 17.5 – 19.5: 3 20 – 22: 3 22.5 – 24.5: 1 25+: 6
Last time: this, debugger
Chapter 4 - Collections
A couple of comments:
1) I’m doing this chapter out of order
2) Some of the code we look at will be a little different than the examples in the
book, because we are using Java 1.5
Collections
Let's consider the quiz scores that we just discussed. Suppose I wanted to write a Java
program that kept track of the quiz scores. What variables would I need?
Now, suppose I wanted to determine the minimum and maximum scores from these
variables.
What if I was teaching at a school where there were 100 students in a class?
So, this is very awkward, and not very flexible.
I'd like to be able to have a general mechanism for keeping a set of values in a list. Java
provides two mechanisms for this:
1) Collection classes in the Java library.
2) Arrays.
We’ll look at one type of Collection first.
Class ArrayList
The Java language comes with hundreds of classes that we can use. These classes
implement commonly needed functions, and allow Java programmers to save time by
using these classes instead of having to write their own.
