eturn</span> <span class="identifier">eof</span><span class="special">;</span>
        <span class="keyword">return</span> <span class="identifier">c_</span><span class="special">++;</span>
    <span class="special">}</span>

    <span class="keyword">static</span> <span class="identifier">result_type</span> <span class="identifier">eof</span><span class="special">;</span>

<span class="keyword">private</span><span class="special">:</span>
    <span class="keyword">char</span> <span class="identifier">c_</s