n class="identifier">r</span> <span class="special">==</span> <span class="identifier">cNegOverflow</span> <span class="special">)</span>
                <span class="keyword">throw</span> <span class="identifier">negative_overflow</span><span class="special">()</span> <span class="special">;</span>
            <span class="keyword">else</span> <span class="keyword">if</span> <span class="special">(</span> <span class="identifier">r</span> <span class="special">==</span> <span class="identifier">cPosOverflo