16周 补充阅读

问题描述：

补充阅读

<code class="hljs cpp has-numbering"><span style="font-family:KaiTi_GB2312;font-size:18px;color:#ff6666;"><strong><span class="hljs-preprocessor">#include <iostream></span>
<span class="hljs-keyword">using</span> <span class="hljs-keyword">namespace</span> <span class="hljs-built_in">std</span>;
<span class="hljs-keyword">void</span> f();
<span class="hljs-keyword">class</span> T
{
<span class="hljs-keyword">public</span>:
    T( )
    {
        <span class="hljs-built_in">cout</span><<<span class="hljs-string">"constructor"</span><<endl;
        <span class="hljs-keyword">try</span>
        {
            <span class="hljs-keyword">throw</span> <span class="hljs-string">"exception"</span>;
        }
        <span class="hljs-keyword">catch</span>(<span class="hljs-keyword">char</span>*)
        {
            <span class="hljs-built_in">cout</span><<<span class="hljs-string">"exception"</span><<endl;
        }
        <span class="hljs-keyword">throw</span> <span class="hljs-string">"exception"</span>;
    }
    ~T( )
    {
        <span class="hljs-built_in">cout</span><<<span class="hljs-string">"destructor"</span>;
    }
};
<span class="hljs-keyword">int</span> main()
{
    <span class="hljs-built_in">cout</span><<<span class="hljs-string">"main function"</span><< endl;
    <span class="hljs-keyword">try</span>
    {
        f( );
    }
    <span class="hljs-keyword">catch</span>(<span class="hljs-keyword">char</span> *)
    {
        <span class="hljs-built_in">cout</span><<<span class="hljs-string">"exception2"</span><<endl;
    }
    <span class="hljs-built_in">cout</span><<<span class="hljs-string">"main function"</span><<endl;
    <span class="hljs-keyword">return</span> <span class="hljs-number">0</span>;
}
<span class="hljs-keyword">void</span> f( )
{
    T t;
}</strong></span></code>

预计运行结果：

main function

constructor

exception

exception

destructor

exception2

main function

实际运行结果：

运行时候指向一个空字符指针！应该
char*p="exception";throw p;

<code class="hljs cpp has-numbering"></code><p></p><span style="font-family: KaiTi_GB2312; font-size: 18px; "><strong><span class="hljs-string">2"</span></strong></span>