r-rouge"><div class="highlight"><pre class="highlight"><code><span class="c1">// preferred</span>
<span class="k">if</span> <span class="p">(</span><span class="n">arg</span> <span class="o">&lt;</span> <span class="mi">0</span><span class="p">)</span> <span class="p">{</span>
    <span class="n">error</span><span class="p">(</span><span class="s">"arg must be positive!"</span><span class="p">);</span>
<span class="p">}</span>
</code></pre></div></div>

<h2 id="efficiency">Efficiency</h2>

<p>In CS106B, we 