STL vector的介绍(1)

标签：c++   stl   vector   

尝试下翻译STL里面的一些容易和算法。四级过了，六级刚考。顺便练练自己的英语水平，翻译的不好的地方请大神多多指教哈，方便我改正。

原来均来自：http://www.cplusplus.com/

template < class T, class Alloc = allocator<T> > class vector; // generic template
Vector
Vectors are sequence containers representing arrays that can change in size.

Just like arrays, vectors use contiguous storage locations for their elements, which means that their elements can also be accessed using offsets on regular pointers 


to its elements, and just as efficiently as in arrays. But unlike arrays, their size can change dynamically, with their storage being handled automatically by the 


container.


Internally, vectors use a dynamically allocated array to store their elements. This array may need to be reallocated in order to grow in size when new elements are 


inserted, which implies allocating a new array and moving all elements to it. This is a relatively expensive task in terms of processing time, and thus, vectors do not 


reallocate each time an element is added to the container.


Instead, vector containers may allocate some extra storage to accommodate for possible growth, and thus the container may have an actual capacity greater than the 


storage strictly needed to contain its elements (i.e., its size). Libraries can implement different strategies for growth to balance between memory usage and 


reallocations, but in any case, reallocations should only happen at logarithmically growing intervals of size so that the insertion of individual elements at the end 


of the vector can be provided with amortized constant time complexity (see push_back).


Therefore, compared to arrays, vectors consume more memory in exchange for the ability to manage storage and grow dynamically in an efficient way.


Compared to the other dynamic sequence containers (deques, lists and forward_lists), vectors are very efficient accessing its elements (just like arrays) and 


relatively efficient adding or removing elements from its end. For operations that involve inserting or removing elements at positions other than the end, they perform 


worse than the others, and have less consistent iterators and references than lists and forward_lists.

相比于其他的动态顺序容器(deques,lists,forward_lists),vector可以非常高效地访问其元素(像array一样高效)以及在尾部增加和删除元素也是相当高效。但是当在尾部以外的位置插入和删除时，它的表现不如其他如list或者是forward_lists容器，并且这会令迭代器以及引用失效。

容器内容：
序列：
在顺序容器里面的元素都严格地排列在一个线性的序列里面。单个元素可以通过他们在序列中的位置直接访问。
动态数组
允许直接访问数组里面的任一元素，甚至是通过指针运算来访问，提供快速在序列尾部添加/删除元素的能力
分配器
容器使用分配器对象来动态地操控其存储所需。


模板参数：
T：
数组vector里面存放的元素类型，
只有T保证不会在移动时抛出异常，当重分配时实现会优化，使用移动元素来代替复制元素（C++11中的移动语义）。
Alloc:
内存分配器对象的类型，一般采用默认值。

//今天就先翻译着一点先。

STL vector的介绍(1),布布扣,bubuko.com

STL vector的介绍(1)

标签：c++   stl   vector   

原文地址：http://blog.csdn.net/qq844352155/article/details/32408253