re>
<p>If the <code class="computeroutput">value_pair's</code> key value is in the map, it's data value is subtraced from the data value stored in the map. </p>
</li>
<li class="listitem"><pre class="literallayout"><a class="link" href="map.html" title="Class template map">map</a> <span class="special">&amp;</span> <a name="idp41736208-bb"></a><span class="identifier">subtract</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">domain_type</span> <span class="spec