假设您有一个有序集，您还想通过添加和删除元素来修改它。此外，您需要能够以这样的方式保留对元素的引用，以便稍后可以获得前一个或下一个元素。例如，一本书中的待办事项列表或一组段落。

首先，我们应该注意到，如果您想在集合本身之外保留对对象的引用，那么您可能最终会将指针存储在数组中，而不是存储对象本身。否则你将无法插入到数组中-如果对象嵌入到数组中，它们将在插入期间移动，并且任何指向它们的指针都将无效。数组下标也是如此。

您的第一个问题，正如您自己所注意到的，是插入链表允许插入O(1)，但数组通常需要O(n)。这个问题可以部分克服——可以创建一种数据结构，提供类似数组的按顺序访问接口，其中读和写在最坏的情况下都是对数的。

Your second, and more severe problem is that given an element finding next element is O(n). If the set was not modified you could retain the index of the element as the reference instead of the pointer thus making find-next an O(1) operation, but as it is all you have is a pointer to the object itself and no way to determine its current index in the array other than by scanning the entire "array". This is an insurmountable problem for arrays - even if you can optimized insertions, there is nothing you can do to optimize find-next type operation.

维基百科上有很好的章节介绍了它们的区别。

Linked lists have several advantages over arrays. Elements can be inserted into linked lists indefinitely, while an array will eventually either fill up or need to be resized, an expensive operation that may not even be possible if memory is fragmented. Similarly, an array from which many elements are removed may become wastefully empty or need to be made smaller. On the other hand, arrays allow random access, while linked lists allow only sequential access to elements. Singly-linked lists, in fact, can only be traversed in one direction. This makes linked lists unsuitable for applications where it's useful to look up an element by its index quickly, such as heapsort. Sequential access on arrays is also faster than on linked lists on many machines due to locality of reference and data caches. Linked lists receive almost no benefit from the cache. Another disadvantage of linked lists is the extra storage needed for references, which often makes them impractical for lists of small data items such as characters or boolean values. It can also be slow, and with a naïve allocator, wasteful, to allocate memory separately for each new element, a problem generally solved using memory pools.

http://en.wikipedia.org/wiki/Linked_list

链表比数组的维护开销更大，它还需要额外的内存存储，所有这些都是一致的。但是有一些事情是数组做不到的。在很多情况下，假设你想要一个长度为10^9的数组你无法得到它，因为必须有一个连续的内存位置。链表可能是这里的救世主。

假设你想用数据存储多个东西，那么它们可以很容易地扩展到链表中。

STL容器通常在后台有链表实现。

两件事:

毫无疑问，编写链表比使用数组要多一些工作，他想知道如何才能证明这些额外的工作是合理的。

使用c++时不要编写链表。使用STL即可。实现的难度不应该成为选择一种数据结构而不是另一种数据结构的理由，因为大多数数据结构都已经实现了。

至于数组和链表之间的实际区别，对我来说最重要的是你计划如何使用这种结构。我将使用术语向量，因为这是c++中可调整大小的数组的术语。

对链表进行索引很慢，因为必须遍历链表才能找到给定的索引，而向量在内存中是连续的，可以使用指针数学方法到达那里。

添加到链表的末尾或开头是很容易的，因为你只需要更新一个链接，而在向量中，你可能需要调整大小并复制内容。

从列表中删除一个项目很容易，因为您只需要断开一对链接，然后将它们重新连接在一起。从向量中移除一个项目可以更快也可以更慢，这取决于您是否关心顺序。在你想要删除的项目上面交换最后一项更快，而移动它之后的所有内容较慢，但保持顺序。

合并两个链表(特别是两个双链表)比合并两个数组快得多(假设合并是破坏性的)。前者取O(1)，后者取O(n)。

编辑:澄清一下，我在这里指的是无序意义上的“合并”，而不是归并排序。也许"串联"这个词更合适。

While many of you have touched upon major adv./dis of linked list vs array, most of the comparisons are how one is better/ worse than the other.Eg. you can do random access in array but not possible in linked list and others. However, this is assuming link lists and array are going to be applied in a similar application. However a correct answer should be how link list would be preferred over array and vice-versa in a particular application deployment. Suppose you want to implement a dictionary application, what would you use ? Array : mmm it would allow easy retrieval through binary search and other search algo .. but lets think how link list can be better..Say you want to search "Blob" in dictionary. Would it make sense to have a link list of A->B->C->D---->Z and then each list element also pointing to an array or another list of all words starting with that letter ..

A -> B -> C -> ...Z
|    |    |
|    |    [Cat, Cave]
|    [Banana, Blob]
[Adam, Apple]

Now is the above approach better or a flat array of [Adam,Apple,Banana,Blob,Cat,Cave] ? Would it even be possible with array ? So a major advantage of link list is you can have an element not just pointing to the next element but also to some other link list/array/ heap/ or any other memory location. Array is a one flat contigous memory sliced into blocks size of the element it is going to store.. Link list on the other hand is a chunks of non-contigous memory units (can be any size and can store anything) and pointing to each other the way you want. Similarly lets say you are making a USB drive. Now would you like files to be saved as any array or as a link list ? I think you get the idea what I am pointing to :)