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which do u prefer? the reason i ask is that most people on these boards seem to be using arrays and not vectors, but the tutorial im using (from cplus.about.com) really seems to downplay the use of arrays and makes it seem like vectors are much better
This isn't a valid poll, of course it depends on the situation. Vectors are not arrays! They are high level data structures that act like arrays (they even have the [] operator overloaded so you can access them like arrays) but they are definitely not arrays. They are most useful when you want to put a new value onto the list, and of course most people find them pretty nifty! :) :) But even when you just want a list of items you may not want a vector, rather you might want a stack, queue, or create your own linked list structures.
Offcourse this depends on situations!
I use arrays normally as C programs.
And in C++ programs I like vector as the code remain pure C++.
But it's just my habit !!! ;) ;) ;)
I think it would've been cool to write the stl vector class. I do admit vectors are very useful.
http://www.parashift.com/c++-faq-lit....html#faq-34.1
I use vectors unless i'm coding time-critical seconds, or using an interface which only supports arrays (e.g. winsock or win32 api)
What do you mean using an interface that only supports arrays? How does win32 only support using arrays?
I prefer to make my own structures like that. I see no use to make a high level class for a simple array.
I've made a linked list template which I'm using in most programs I need a list in, and it's working great.
Eh? Are Swedes that cool, huh? :cool:Quote:
Silvercord
I'm not really from Sweden, but everyone seems to think people from Sweden are cool, so I'm just pretending to be from Sweden so more people will like me
the underlying structure in the STL are linked lists (for vectors, maps, lists, sets, etc....). handy to use, but slow when every little cycle counts. (ruins the cache 'predictions')
i prefer making my own dynamic structures that reallocate into new arrays, keeping everything consecutive in memory. although this does make 'expanding' slower, run time access is faster.
its really not a huge difference but this programmer from EA gave a seminar at my school and said "stay away from the STL when game programming..."
You are right in saying that there are times when I'd rather use a stack or queue for my container, but I can't think of a time I'd rather use an array over a vector. I know that's just due to my laziness, but I feel that I am competant enough with arrays that I don't have to prove to others that I know how to use them. Vectors are so useful to me because they afford me many of the pros of arrays without making me worry about the cons. resize() is so much nicer than having to worry about how much to new or delete.
I must admit though that I am not a professional programmer, so I rarely worry about subtle performance differences. I'm sure that arrays are better on memory and processor speed, but their a pain to use in my opinion.
Short thread on the topic.
gg
I have never used a vector<>
I usually prefer vectors, they are just so much easier and flexible than arrays imo.
I do use arrays though for small constant containers. Also if I don't feel like digging out my matrix class, I use arrays for two-dimensional structures which vectors are a pain to use.
What do ye mean by vectors. Are ye talking about linked list.
Isn't an array just like a fixed pointer and indexing into it is like pointer arithmetic.
array[10]
&array + 10
Maybe I am all wrong on this.
Quote:
Originally posted by spidereen
What do ye mean by vectors. Are ye talking about linked list.
Isn't an array just like a fixed pointer and indexing into it is like pointer arithmetic.
array[10]
&array + 10
Maybe I am all wrong on this.
vectors are ADT's from the standard template library. at base level they are linked lists. they are different from arrays because they are dynamic (expandable) and are not necessarilly consecutive in memory. Arrays on the other hand are consectutive in memory and there for can be indexed as in your example.
No, actually you're wrong here. A vector is usually implemented as an array, NOT a linked list. they "expand" by reallocating and/or reserving memory. This I am sure of.Quote:
Originally posted by Perspective
vectors are ADT's from the standard template library. at base level they are linked lists. they are different from arrays because they are dynamic (expandable) and are not necessarilly consecutive in memory. Arrays on the other hand are consectutive in memory and there for can be indexed as in your example.
Also, I may be mistaken in this last part as I don't usually use the STL, but I believe it may even be required that a vector occupies consecutive space in memory.
hmmm, i was actually taught that way too (in java). but like i said above ( i think it was this thread), this guy from EA said the STL was evil because its ADT's are based on linked lists. either way, i prefer to write my own. :)Quote:
Originally posted by Polymorphic OOP
No, actually you're wrong here. A vector is usually implemented as an array, NOT a linked list. they "expand" by reallocating and/or reserving memory. This I am sure of.
Whats an array?!:D
Serious question: What are the advantages of using a linked list? When should one use a linked list instead of an array or vector? From what little I've seen, linked lists just look like a hassle to use.
linked list can save you on memory. however, you have to use sequential search. arrays and vectors can be searched with binary or random access. but at the same time, can take up more memory. it depends on what you are using it for and which you feel is the best to use in the situation.Quote:
Originally posted by joshdick
Serious question: What are the advantages of using a linked list? When should one use a linked list instead of an array or vector? From what little I've seen, linked lists just look like a hassle to use.
You got it mixed up. linked lists will actually take up more memory than arrays because each node in a linked list has to have a pointer to at least one other node.Quote:
Originally posted by alpha
linked list can save you on memory...
arrays and vectors ... can take up more memory
The reasons you use a linked list is because you can add and remove elements (particularly adding and removing elements in the middle of the list) without having to reallocate any memory that has values which aren't changing, while with an array, you will many times have to completely reallocate more memory and copy all of the data over, and to remove an element in an array, you have to copy all the ones after it back one space.
It's all about data access, creation, and removal -- are you going to be adding and removing a lot of something, more particularly, are you going to be adding and removing a lot of something in no predefined order. If so, then a linked list makes much more sense. An example would be a game with a bunch of enemies on the screen. You have no idea what order the player will be killing the enemies in, so you use a linked list making it more efficient to remove an element from the middle.
You can usually use arrays as stacks or queues of predetermined maximum lenght. One perfect example I can give of this is "the stack" that you should be familiar with as a C++ programmer. If not, then go back to lesson 1 :p
Thanks. That makes much more sense.Quote:
Originally posted by Polymorphic OOP
You got it mixed up. linked lists will actually take up more memory than arrays because each node in a linked list has to have a pointer to at least one other node.
Assuming the array is filled, then that's true.Quote:
You got it mixed up. linked lists will actually take up more memory than arrays because each node in a linked list has to have a pointer to at least one other node.
However, if you're having a variable amount of data, an array must have enough room for extra elements, while a linked list only allocates what it needs. This usually leads to sizeof(Array) > sizeof(LinkedList).
that's true too. i think that's what i was thinking when i posted it. assuming you only have a few nodes and a big array, then the linked list should take up less memory. but assuming the same size for linked list and array, then array should take up less space.Quote:
Originally posted by Magos
Assuming the array is filled, then that's true.
However, if you're having a variable amount of data, an array must have enough room for extra elements, while a linked list only allocates what it needs. This usually leads to sizeof(Array) > sizeof(LinkedList).
I just read this article and it says you should prefer deques over vectors:
http://www.gotw.ca/publications/mill10.htm
Should i consider myself sociaal outcast upon finding this discussion entertaining reading???
yes.Quote:
Originally posted by DirX
Should i consider myself sociaal outcast upon finding this discussion entertaining reading???
darn...... thats not good :eek: