Lecture 1 March 31st 2014 1 Array limitations fixed size adding or removing from middle is hard not much built in functionality needs Arrays class 2 Collections and lists collection an object that stores data elements list collection of elements with 0 based indexes elements can be added to the front back or elsewhere a list has a size number of elements that have been added in Java list can be represented as an ArrayList Object 3 Type parameters generics ArrayList Type name new ArrayList Type 4 ArrayList methods add value appends value at end of list add index value inserts given value just before the given index shifting subsequent values to the right clear removes all elements of the list indexOf value returns first index where given value is found in list 1 if not found get index returns the value at given index remove index removes returns value at given idex shifting subsequence values to the left set index value replaces value at given index with given value size returns number of elements in list toString returns string as num num import java util public class Lecture1 public static void main String args String people new String 6 Using an Array is bad because it constrains the size before number of elements is even known ArrayList String people new ArrayList String people add Robert System out println people System out println people size ArrayList basically same as Array just that size is not constrained prior public class ReverseFile public static void main String args throws FileNotFoundException Capitalize all plural words for int i 0 i words size i if words get i endsWith s words set i words get i toUpperCase Remove all plural words THIS DOES NOT WORK BECAUSE everything slides over to the left when you remove an element for int i 0 i words size i if words get i endsWith s words remove i i HAVE TO ADD THIS System out println words for int i words size 1 i 0 i System out println words get i Must include the throws in whatever scans a file public static ArrayList String fileToArrayList String fileName throws FileNotFoundException Scanner input new Scanner new File fileName ArrayList String words new ArrayList String while input hasNext words add input next