Hi The interface collection leaves to you do everithing that you want using any kind of list . So you should read about them, perhaps it'll helps to you. For remove any element of the list you can make it saying to the list the index of your element. Or you can create a function that delete the element that you want. For add element the list or collection haVe two options or three isla good watch the api of java. And if the list or collection grow you can control that in the constructor of the collection. I like use the vector class
I hope help you. Luck and see you 2011/1/5, Mihai DINCA <mihai.di...@free.fr>: > Hi Eliscinsky > > The ArrayList is implemented using an array: > -- If you add more elements than the array size, then a new bigger array > is (probably) created and the elements are copied from the old into the > new one > -- When you insert an element at any position except at the end and when > you delete an element at any position except the end, then the remaining > elements (probably) must be moved one by one > -- En exchange to the above time consuming operations, you can read the > value of the "n"th element directly (direct access) > > The LinkedList is implemented as a double linked list: > -- If you need the "n"th element in the list, then all the elements > (probably) from the closest end and up to the "n"th element must be read > -- But you can easily insert or supress elements at any position > > In brief: > -- If you need to access only the first or the last element of the list > (such as when implementing a queue or a heap) or if your need a storage > for elements that are oftenly added/removed, then use a LinkedList > -- If you need a storage for a predictable number of elements that > almost never change but you need a quick direct access to the elements, > then use an ArrayList > -- If you don't know which is better, then use the List interface and > specify the list implementation only in the constructor (such as > List myList = new ArrayList(); > ). Run once with an ArrayList and once with a LinkedList, compare > performances then choose the better. > > Hope it helps > Mihai > > Le 05/01/2011 19:53, eliscinsky a écrit : >> In Exercise 2, second paragraph states ... >> >> There are two general-purpose List implementations in the Collections >> Framework: ArrayList and LinkedList. Which of the two List >> implementations you use depends on your specific needs. If you need to >> support random access, with inserting or removing elements from any >> place other than the end, then ArrayList offers the optimal >> collection. If, however, you need to frequently add and remove >> elements from the middle of the list and only access the list elements >> sequentially then LinkedList offers the better implementation. >> >> My confusion is this ... >> >> A) If ... inserting or removing ... any place other than the end, then >> ArrayList offers the optimal collection. >> >> "any place other than the end" - This means adding and removing from >> the middle of the List. Correct? >> >> B) If, however, ... add and remove elements from the middle ... then >> LinkedList offers the better implementation. >> >> "add and remove elements from the middle" - This also means adding and >> removing from the middle of the List. Correct? >> >> But as stated from JavaDoc of the LinkedList (http:// >> download.oracle.com/javase/1.5.0/docs/api/index.html?java/util/ >> ArrayList.html), which notes "remove and insert an element at the >> beginning and end of the list" >> >> Linked list implementation of the List interface. Implements all >> optional list operations, and permits all elements (including null). >> In addition to implementing the List interface, the LinkedList class >> provides uniformly named methods to get, remove and insert an element >> at the beginning and end of the list. These operations allow linked >> lists to be used as a stack, queue, or double-ended queue (deque). >> >> >> Please advise. >> > > -- > To post to this group, send email to > javaprogrammingwithpassion@googlegroups.com > To unsubscribe from this group, send email to > javaprogrammingwithpassion+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/javaprogrammingwithpassion?hl=en -- Enviado desde mi dispositivo móvil Cordiamente, Freddy Castelblanco Macías -- To post to this group, send email to javaprogrammingwithpassion@googlegroups.com To unsubscribe from this group, send email to javaprogrammingwithpassion+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/javaprogrammingwithpassion?hl=en
