C++ 标准模板库STL中vector用法介绍

蔚落 2022-05-31 04:49 353阅读 0赞

本文所介绍的std::vector用法基于C++11，std::vector定义于头文件<vector>中，其定义如下：

template<
 class T,
 class Allocator = std::allocator<T>
 > class vector;

其包含成员类型其成员函数如下：

### 成员类型 ###

<table> 
 <tbody> 
 <tr> 
 <th>成员类型</th> 
 <th>定义</th> 
 </tr> 
 </tbody> 
 <tbody> 
 <tr> 
 <td>value_type</td> 
 <td>T</td> 
 </tr> 
 <tr> 
 <td>allocator_type</td> 
 <td>Allocator</td> 
 </tr> 
 <tr> 
 <td>size_type</td> 
 <td>无符号整数类型（通常是std::size_t&nbsp;）</td> 
 </tr> 
 <tr> 
 <td>difference_type</td> 
 <td>有符号整数类型（通常是std::ptrdiff_t&nbsp;）</td> 
 </tr> 
 <tr> 
 <td>reference</td> 
 <td>value_type&amp;</td> 
 </tr> 
 <tr> 
 <td>const_reference</td> 
 <td>const value_type&amp;</td> 
 </tr> 
 <tr> 
 <td>pointer</td> 
 <td>std::allocator_traits&lt;Allocator&gt;::pointer </td> 
 </tr> 
 <tr> 
 <td>const_pointer </td> 
 <td>std::allocator_traits&lt;Allocator&gt;::const_pointer</td> 
 </tr> 
 <tr> 
 <td>iterator</td> 
 <td>随机访问迭代器&nbsp;(<code style="background-color:rgb(255,255,255);font-size:12.8px;font-family:DejaVuSansMono, 'DejaVu Sans Mono', courier, monospace;">RandomAccessIterator</code>) </td> 
 </tr> 
 <tr> 
 <td>const_iterator </td> 
 <td>常随机访问迭代器 </td> 
 </tr> 
 <tr> 
 <td>reverse_iterator </td> 
 <td>std::reverse_iterator&lt;iterator&gt; </td> 
 </tr> 
 <tr> 
 <td>const_reverse_iterator </td> 
 <td>std::reverse_iterator&lt;const_iterator&gt;</td> 
 </tr> 
 </tbody> 
</table>

### 成员函数 ###

<table> 
 <tbody> 
 <tr> 
 <th>成员函数</th> 
 <th>作用</th> 
 </tr> 
 </tbody> 
 <tbody> 
 <tr> 
 <td>（构造函数）</td> 
 <td>构造&nbsp;<code style="background-color:rgb(255,255,255);font-size:12.8px;font-family:DejaVuSansMono, 'DejaVu Sans Mono', courier, monospace;">vector</code></td> 
 </tr> 
 <tr> 
 <td>（析构函数）</td> 
 <td>析构&nbsp;<code style="background-color:rgb(255,255,255);font-size:12.8px;font-family:DejaVuSansMono, 'DejaVu Sans Mono', courier, monospace;">vector</code></td> 
 </tr> 
 <tr> 
 <td>operator= </td> 
 <td>赋值给容器 </td> 
 </tr> 
 <tr> 
 <td>assign(size_type count,&nbsp;const&nbsp;T&amp;&nbsp;value) assign(InputIt first, InputIt last) assign(std::initializer_list&lt;T&gt;&nbsp;ilist) </td> 
 <td>替换容器的内容 </td> 
 </tr> 
 <tr> 
 <td>get_allocator()</td> 
 <td>返回相关的分配器</td> 
 </tr> 
 </tbody> 
</table>

#### 1、元素访问 ####

<table> 
 <tbody> 
 <tr> 
 <td>at(size_type pos) </td> 
 <td>访问指定的元素，同时进行越界检查 若&nbsp;<code style="color:rgb(0,0,0);background-color:rgb(255,255,255);font-size:12.8px;font-family:DejaVuSansMono, 'DejaVu Sans Mono', courier, monospace;">pos</code>&nbsp;不在容器范围内，则抛出&nbsp;std::out_of_range&nbsp;类型的异常 </td> 
 </tr> 
 <tr> 
 <td>operator[] </td> 
 <td>访问指定的元素 </td> 
 </tr> 
 <tr> 
 <td>front() </td> 
 <td>访问第一个元素 </td> 
 </tr> 
 <tr> 
 <td>back() </td> 
 <td>访问最后一个元素 </td> 
 </tr> 
 <tr> 
 <td>data() </td> 
 <td>返回指向内存中数组第一个元素的指针</td> 
 </tr> 
 </tbody> 
</table>

#### 2、迭代器 ####

<table> 
 <tbody> 
 <tr> 
 <td>begin() cbegin()</td> 
 <td>返回指向容器第一个元素的迭代器</td> 
 </tr> 
 <tr> 
 <td>end() cend()</td> 
 <td>返回指向容器尾端的迭代器</td> 
 </tr> 
 <tr> 
 <td>rbegin() crbegin()</td> 
 <td>返回一个指向容器最后一个元素的反向迭代器</td> 
 </tr> 
 <tr> 
 <td>rend() crend()</td> 
 <td>返回一个指向容器前端的反向迭代器&nbsp;</td> 
 </tr> 
 </tbody> 
</table>

#### 3、容量 ####

#### 4、修改器 ####

<table> 
 <tbody> 
 <tr> 
 <td>clear() </td> 
 <td>清除内容&nbsp; </td> 
 </tr> 
 <tr> 
 <td>insert(const_iterator pos,&nbsp;const&nbsp;T&amp;&nbsp;value) insert(const_iterator pos, T&amp;&amp;&nbsp;value) insert(const_iterator pos, size_type count,&nbsp;const&nbsp;T&amp;&nbsp;value) insert(const_iterator pos, InputIt first, InputIt last) insert(const_iterator pos,&nbsp;std::initializer_list&lt;T&gt;&nbsp;ilist) </td> 
 <td>插入元素&nbsp; </td> 
 </tr> 
 <tr> 
 <td>emplace(const_iterator pos, Args&amp;&amp;...&nbsp;args) </td> 
 <td>直接于&nbsp;<code style="background-color:rgb(255,255,255);font-size:12.8px;font-family:DejaVuSansMono, 'DejaVu Sans Mono', courier, monospace;">pos</code>&nbsp;前插入元素到容器中，将参数&nbsp;<code style="background-color:rgb(255,255,255);font-size:12.8px;font-family:DejaVuSansMono, 'DejaVu Sans Mono', courier, monospace;">args...转发给构造函数</code> </td> 
 </tr> 
 <tr> 
 <td>erase(iterator pos) erase(iterator first, iterator last) </td> 
 <td>擦除元素或一段序列 </td> 
 </tr> 
 <tr> 
 <td>push_back(const T&amp; x) </td> 
 <td>将元素x添加到容器末尾&nbsp; </td> 
 </tr> 
 <tr> 
 <td>emplace_back(Args<span style="color:rgb(0,0,0);font-family:DejaVuSansMono, 'DejaVu Sans Mono', courier, monospace;font-size:12.8px;font-weight:700;white-space:nowrap;line-height:1.1em;margin:0px;padding:0px;background-color:rgb(255,255,255);">&amp;&amp;...&nbsp;<span style="color:rgb(0,0,0);font-family:DejaVuSansMono, 'DejaVu Sans Mono', courier, monospace;font-size:12.8px;font-weight:700;white-space:nowrap;line-height:1.1em;margin:0px;padding:0px;background-color:rgb(255,255,255);">args) </td> 
 <td>在容器末尾就地构造元素&nbsp; </td> 
 </tr> 
 <tr> 
 <td>pop_back() </td> 
 <td>移除末元素&nbsp; </td> 
 </tr> 
 <tr> 
 <td>resize(size_type sz, T c = T()) </td> 
 <td>改变容器中可存储元素的个数 若重新分配的元素个数比原来的小，则截断序列 若比原来的的大，后面的值是c的值，默认为0 </td> 
 </tr> 
 <tr> 
 <td>swap(vector&amp; other)</td> 
 <td>交换内容</td> 
 </tr> 
 </tbody> 
</table>

##### 5、非成员函数 #####

<table> 
 <tbody> 
 <tr> 
 <td>operator== operator!= operator&lt; operator&lt;= operator&gt; operator&gt;=</td> 
 <td>按照字典顺序比较 vector 中的值</td> 
 </tr> 
 </tbody> 
</table>