PHP 中的构造函数

<code>
<code class="language-php hljs" data-lang="php"><span style="display:flex;"><span><span style="color:#666"></span>php
</span></span><span style="display:flex;"><span><span style="color:#008000;font-weight:bold">class</span> <span style="color:#00f;font-weight:bold">Student</span>
</span></span><span style="display:flex;"><span>{
</span></span><span style="display:flex;"><span>	<span style="color:#008000;font-weight:bold">public</span> <span style="color:#19177c">$name</span>;
</span></span><span style="display:flex;"><span>	<span style="color:#008000;font-weight:bold">public</span> <span style="color:#008000;font-weight:bold">function</span> __construct(<span style="color:#19177c">$name</span>)
</span></span><span style="display:flex;"><span>	{
</span></span><span style="display:flex;"><span>		<span style="color:#19177c">$this</span><span style="color:#666">-&gt;</span><span style="color:#7d9029">name</span> <span style="color:#666">=</span> <span style="color:#19177c">$name</span>;
</span></span><span style="display:flex;"><span>	}
</span></span><span style="display:flex;"><span>}<span style="color:#008000;font-weight:bold">class</span> <span style="color:#00f;font-weight:bold">Identity</span> <span style="color:#008000;font-weight:bold">extends</span> Student
</span></span><span style="display:flex;"><span>{
</span></span><span style="display:flex;"><span>	<span style="color:#008000;font-weight:bold">public</span> <span style="color:#19177c">$identity_id</span>;
</span></span><span style="display:flex;"><span>	
</span></span><span style="display:flex;"><span>	<span style="color:#008000;font-weight:bold">public</span> <span style="color:#008000;font-weight:bold">function</span> __construct(<span style="color:#19177c">$name</span>, <span style="color:#19177c">$identity_id</span>)
</span></span><span style="display:flex;"><span>	{
</span></span><span style="display:flex;"><span>		<span style="color:#008000;font-weight:bold">parent</span><span style="color:#666">::</span><span style="color:#7d9029">__construct</span>(<span style="color:#19177c">$name</span>);
</span></span><span style="display:flex;"><span>		<span style="color:#19177c">$this</span><span style="color:#666">-&gt;</span><span style="color:#7d9029">identity_id</span> <span style="color:#666">=</span> <span style="color:#19177c">$identity_id</span>;
</span></span><span style="display:flex;"><span>	}
</span></span><span style="display:flex;"><span>	<span style="color:#008000;font-weight:bold">function</span> <span style="color:#00f">show_detail</span>() {
</span></span><span style="display:flex;"><span>		<span style="color:#008000;font-weight:bold">echo</span> <span style="color:#19177c">$this</span><span style="color:#666">-&gt;</span><span style="color:#7d9029">name</span><span style="color:#666">.</span><span style="color:#ba2121">" : "</span>;
</span></span><span style="display:flex;"><span>		<span style="color:#008000;font-weight:bold">echo</span> <span style="color:#ba2121">"Your Id Number is "</span><span style="color:#666">.</span><span style="color:#19177c">$this</span><span style="color:#666">-&gt;</span><span style="color:#7d9029">identity_id</span><span style="color:#666">.</span><span style="color:#ba2121">"</span><span style="color:#b62;font-weight:bold">

</span><span style="color:#ba2121">"</span>;
</span></span><span style="display:flex;"><span>	}
</span></span><span style="display:flex;"><span>}
</span></span><span style="display:flex;"><span><span style="color:#19177c">$obj</span> <span style="color:#666">=</span> <span style="color:#008000;font-weight:bold">new</span> Identity(<span style="color:#ba2121">'Alice'</span>, <span style="color:#ba2121">'1036398'</span>);
</span></span><span style="display:flex;"><span><span style="color:#008000;font-weight:bold">echo</span> <span style="color:#19177c">$obj</span><span style="color:#666">-&gt;</span><span style="color:#7d9029">show_detail</span>();
</span></span><span style="display:flex;"><span><span style="color:#bc7a00">?&gt;</span><span >
</span></span></span></code></code>