[c++]代理对象模式

代理对象

<code class="hljs cpp has-numbering" style="display: block; padding: 0px; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-image: initial; background-attachment: initial; background-color: transparent; background-size: initial; background-origin: initial; background-clip: initial; background-position: initial; background-repeat: initial;"><span style="color: inherit;"><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">#include <iostream></span>
<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">#include <vector></span></span></code><code class="hljs cpp has-numbering" style="display: block; padding: 0px; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-image: initial; background-attachment: initial; background-color: transparent; background-size: initial; background-origin: initial; background-clip: initial; background-position: initial; background-repeat: initial;">#include <string>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">using</span><span style="color:rgba(0, 0, 0, 0);"> </span><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">namespace</span><span style="color:rgba(0, 0, 0, 0);"> </span><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">std</span><span style="color:rgba(0, 0, 0, 0);">;
</span><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span><span style="color:rgba(0, 0, 0, 0);"> </span><span style="color:#ff0000;">Vehicle </span></code><code class="hljs cpp has-numbering" style="display: block; padding: 0px; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-image: initial; background-attachment: initial; background-color: transparent; background-size: initial; background-origin: initial; background-clip: initial; background-position: initial; background-repeat: initial;"><span style="color: inherit;">{<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span>:Vehicle() {}<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">virtual</span> <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">string</span> getName() = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>;
};<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> Car : <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> </span><span style="color:#ff0000;">Vehicle </span></code><code class="hljs cpp has-numbering" style="color: inherit; display: block; padding: 0px; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-image: initial; background-attachment: initial; background-color: transparent; background-size: initial; background-origin: initial; background-clip: initial; background-position: initial; background-repeat: initial;">{<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span>:Car() </code><code class="hljs cpp has-numbering" style="color: inherit; display: block; padding: 0px; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-image: initial; background-attachment: initial; background-color: transparent; background-size: initial; background-origin: initial; background-clip: initial; background-position: initial; background-repeat: initial;">  {name = <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"car"</span>;}<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">virtual</span> <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">string</span> getName() </code><code class="hljs cpp has-numbering" style="color: inherit; display: block; padding: 0px; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-image: initial; background-attachment: initial; background-color: transparent; background-size: initial; background-origin: initial; background-clip: initial; background-position: initial; background-repeat: initial;">  {<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> name; </code><code class="hljs cpp has-numbering" style="color: inherit; display: block; padding: 0px; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-image: initial; background-attachment: initial; background-color: transparent; background-size: initial; background-origin: initial; background-clip: initial; background-position: initial; background-repeat: initial;">  }~Car() </code><code class="hljs cpp has-numbering" style="display: block; padding: 0px; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-image: initial; background-attachment: initial; background-color: transparent; background-size: initial; background-origin: initial; background-clip: initial; background-position: initial; background-repeat: initial;"><span style="color: inherit;">  {<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">cout</span> << <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"delete"</span> << endl;}
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span>:<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">string</span> name;
};<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> Bike : <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> </span><span style="color:#ff0000;">Vehicle </span></code><code class="hljs cpp has-numbering" style="color: inherit; display: block; padding: 0px; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-image: initial; background-attachment: initial; background-color: transparent; background-size: initial; background-origin: initial; background-clip: initial; background-position: initial; background-repeat: initial;">{<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span>:Bike() {}<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">virtual</span> <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">string</span> getName() { <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"bike"</span>; }
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span>:<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">string</span> name;
};</code><code class="hljs cpp has-numbering" style="color: inherit; display: block; padding: 0px; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-image: initial; background-attachment: initial; background-color: transparent; background-size: initial; background-origin: initial; background-clip: initial; background-position: initial; background-repeat: initial;">
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> wrong_code(<span class="hljs-stl_container" style="box-sizing: border-box;"><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">vector</span><Vehicle *></span> &parkinglot) </code><code class="hljs cpp has-numbering" style="color: inherit; display: block; padding: 0px; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-image: initial; background-attachment: initial; background-color: transparent; background-size: initial; background-origin: initial; background-clip: initial; background-position: initial; background-repeat: initial;">{Car c;<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">cout</span> << &c << endl;parkinglot[<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>] = &c;  <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//将c插入到parkinglot内</span><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">cout</span> << &(*parkinglot[<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>]) << endl;
}</code><code class="hljs cpp has-numbering" style="color: inherit; display: block; padding: 0px; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-image: initial; background-attachment: initial; background-color: transparent; background-size: initial; background-origin: initial; background-clip: initial; background-position: initial; background-repeat: initial;">
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> main() </code><code class="hljs cpp has-numbering" style="color: inherit; display: block; padding: 0px; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-image: initial; background-attachment: initial; background-color: transparent; background-size: initial; background-origin: initial; background-clip: initial; background-position: initial; background-repeat: initial;">{<span class="hljs-stl_container" style="box-sizing: border-box;"><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">vector</span><Vehicle *></span> parkinglot(<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>);wrong_code(parkinglot);<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">cout</span> << parkinglot[<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>]->getName() << endl;  <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// Oops!!parkinglot内存的地址指向了一块被销毁的内存</span><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">cout</span> << &(*parkinglot[<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>]) << endl;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>;
}</code><ul class="pre-numbering" style="color: rgb(51, 51, 51); box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li><li style="box-sizing: border-box; padding: 0px 5px;">35</li><li style="box-sizing: border-box; padding: 0px 5px;">36</li><li style="box-sizing: border-box; padding: 0px 5px;">37</li><li style="box-sizing: border-box; padding: 0px 5px;">38</li><li style="box-sizing: border-box; padding: 0px 5px;">39</li><li style="box-sizing: border-box; padding: 0px 5px;">40</li><li style="box-sizing: border-box; padding: 0px 5px;">41</li><li style="box-sizing: border-box; padding: 0px 5px;">42</li><li style="box-sizing: border-box; padding: 0px 5px;">43</li></ul>

0x7fff5fbff6d8 
0x7fff5fbff6d8 
delete

<code class="hljs javascript has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background: transparent;">
<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0x7fff5fbff6d8</span>
<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0x7fff5fbff6d8</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">delete</span>
乱码。。。。
<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0x7fff5fbff6d8</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li></ul>

在这种情况下会出现因为临时对象在生命周期结束之后,对象上的内存被释放,所以访问它的数据就会出现不可预计的结果。

在这种大前提下,代理类就顺势而生了.

顾名思义,代理类就是指某个基类以及其子类的代理,其功能是使之能在容器中也表现出多态性.而没有动态内存管理的烦恼.

现在定义Vehicle以及子类的代理类VehicleSurrogate.

<code class="hljs cpp has-numbering" style="color: inherit; display: block; padding: 0px; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-image: initial; background-attachment: initial; background-color: transparent; background-size: initial; background-origin: initial; background-clip: initial; background-position: initial; background-repeat: initial;"><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">#include <iostream></span>
<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">#include <vector></span></code><code class="hljs cpp has-numbering" style="display: block; padding: 0px; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-image: initial; background-attachment: initial; background-color: transparent; background-size: initial; background-origin: initial; background-clip: initial; background-position: initial; background-repeat: initial;">#include <string>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">using</span><span style="color:rgba(0, 0, 0, 0);"> </span><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">namespace</span><span style="color:rgba(0, 0, 0, 0);"> </span><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">std</span><span style="color:rgba(0, 0, 0, 0);">;</span><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span><span style="color:rgba(0, 0, 0, 0);"> Vehicle </span></code><code class="hljs cpp has-numbering" style="color: inherit; display: block; padding: 0px; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-image: initial; background-attachment: initial; background-color: transparent; background-size: initial; background-origin: initial; background-clip: initial; background-position: initial; background-repeat: initial;">{<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span>:Vehicle() {}<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">virtual</span> <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">string</span> getName() = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">virtual</span> Vehicle *copy() <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">const</span> = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">virtual</span> ~Vehicle() {}  <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//虚析构函数是为了支持多态.但是本例中并不需要.</span><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span>:
};<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> Car : <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> Vehicle </code><code class="hljs cpp has-numbering" style="color: inherit; display: block; padding: 0px; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-image: initial; background-attachment: initial; background-color: transparent; background-size: initial; background-origin: initial; background-clip: initial; background-position: initial; background-repeat: initial;">{<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span>:Car() { name = <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"car"</span>; }<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">virtual</span> <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">string</span> getName() { <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> name; }<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">virtual</span> Vehicle *copy() <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">const</span> { <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Car; }<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">virtual</span> ~Car() {}<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span>:<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">string</span> name;
};<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> Bike : <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> Vehicle </code><code class="hljs cpp has-numbering" style="display: block; padding: 0px; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-image: initial; background-attachment: initial; background-color: transparent; background-size: initial; background-origin: initial; background-clip: initial; background-position: initial; background-repeat: initial;"><span style="color: inherit;">{<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span>:Bike() { name = <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"bike"</span>; }<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">virtual</span> <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">string</span> getName() { <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> name; }<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">virtual</span> Vehicle *copy() <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">const</span> { <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Bike; }<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">virtual</span> ~Bike() {}<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span>:<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">string</span> name;
};<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> </span><span style="color:#ff0000;">VehicleSurrogate </span></code><code class="hljs cpp has-numbering" style="color: inherit; display: block; padding: 0px; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-image: initial; background-attachment: initial; background-color: transparent; background-size: initial; background-origin: initial; background-clip: initial; background-position: initial; background-repeat: initial;">{<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span>:VehicleSurrogate() : p(<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>) {}VehicleSurrogate(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">const</span> Vehicle &v) : p(v.copy()) {}VehicleSurrogate(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">const</span> VehicleSurrogate &vs) : p(vs.p ? vs.p->copy() : <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>) {}VehicleSurrogate &<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">operator</span>=(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">const</span> VehicleSurrogate &vs) {<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span> != &vs)  <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//在删除p之前一定得记得判断vs和this是不是同一个,否则会有问题</span>{<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">delete</span> p;p = vs.p->copy();}<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> *<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>;}<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">string</span> getName() { <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> p->getName(); }~VehicleSurrogate() { <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">delete</span> p; }<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span>:Vehicle *p;
};</code><code class="hljs cpp has-numbering" style="color: inherit; display: block; padding: 0px; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-image: initial; background-attachment: initial; background-color: transparent; background-size: initial; background-origin: initial; background-clip: initial; background-position: initial; background-repeat: initial;">
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> right_code(<span class="hljs-stl_container" style="box-sizing: border-box;"><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">vector</span><VehicleSurrogate></span> &parkinglot) </code><code class="hljs cpp has-numbering" style="color: inherit; display: block; padding: 0px; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-image: initial; background-attachment: initial; background-color: transparent; background-size: initial; background-origin: initial; background-clip: initial; background-position: initial; background-repeat: initial;">{Car c;parkinglot.push_back(c);
}</code><code class="hljs cpp has-numbering" style="color: inherit; display: block; padding: 0px; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-image: initial; background-attachment: initial; background-color: transparent; background-size: initial; background-origin: initial; background-clip: initial; background-position: initial; background-repeat: initial;">
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> main() </code><code class="hljs cpp has-numbering" style="color: inherit; display: block; padding: 0px; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-image: initial; background-attachment: initial; background-color: transparent; background-size: initial; background-origin: initial; background-clip: initial; background-position: initial; background-repeat: initial;">{<span class="hljs-stl_container" style="box-sizing: border-box;"><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">vector</span><VehicleSurrogate></span> parkinglot;right_code(parkinglot);<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">cout</span> << parkinglot[<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>].getName() << endl;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>;
}</code><ul class="pre-numbering" style="color: rgb(51, 51, 51); box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li><li style="box-sizing: border-box; padding: 0px 5px;">35</li><li style="box-sizing: border-box; padding: 0px 5px;">36</li><li style="box-sizing: border-box; padding: 0px 5px;">37</li><li style="box-sizing: border-box; padding: 0px 5px;">38</li><li style="box-sizing: border-box; padding: 0px 5px;">39</li><li style="box-sizing: border-box; padding: 0px 5px;">40</li><li style="box-sizing: border-box; padding: 0px 5px;">41</li><li style="box-sizing: border-box; padding: 0px 5px;">42</li><li style="box-sizing: border-box; padding: 0px 5px;">43</li><li style="box-sizing: border-box; padding: 0px 5px;">44</li><li style="box-sizing: border-box; padding: 0px 5px;">45</li><li style="box-sizing: border-box; padding: 0px 5px;">46</li><li style="box-sizing: border-box; padding: 0px 5px;">47</li><li style="box-sizing: border-box; padding: 0px 5px;">48</li><li style="box-sizing: border-box; padding: 0px 5px;">49</li><li style="box-sizing: border-box; padding: 0px 5px;">50</li><li style="box-sizing: border-box; padding: 0px 5px;">51</li><li style="box-sizing: border-box; padding: 0px 5px;">52</li><li style="box-sizing: border-box; padding: 0px 5px;">53</li><li style="box-sizing: border-box; padding: 0px 5px;">54</li><li style="box-sizing: border-box; padding: 0px 5px;">55</li><li style="box-sizing: border-box; padding: 0px 5px;">56</li><li style="box-sizing: border-box; padding: 0px 5px;">57</li><li style="box-sizing: border-box; padding: 0px 5px;">58</li><li style="box-sizing: border-box; padding: 0px 5px;">59</li><li style="box-sizing: border-box; padding: 0px 5px;">60</li><li style="box-sizing: border-box; padding: 0px 5px;">61</li><li style="box-sizing: border-box; padding: 0px 5px;">62</li><li style="box-sizing: border-box; padding: 0px 5px;">63</li><li style="box-sizing: border-box; padding: 0px 5px;">64</li><li style="box-sizing: border-box; padding: 0px 5px;">65</li></ul>
<code class="hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background: transparent;">car</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

所以,这种代理对象的模式实际上就是对对象的封装,同时处理他们对他们进行资源管理,从而防止指针对象指向未被析构的对象地址,已经内存泄露的问题。

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