><span class="special">&gt;</span>
<span class="keyword">void</span> <span class="identifier">subtract_point</span><span class="special">(</span><span class="identifier">Point1</span> <span class="special">&amp;</span> <span class="identifier">p1</span><span class="special">,</span> <span class="identifier">Point2</span> <span class="keyword">const</span> <span class="special">&amp;</span> <span class="identifier">p2</span><span class="special">)</span></pre>
<p>
        </p>
<h6>
<a name="geometry.referenc