output"><span class="identifier">map</span><span class="special">&lt;</span><span class="identifier">K</span><span class="special">,</span><span class="identifier">D</span><span class="special">&gt;</span></code> the
        first parameter type of the map template <code class="computeroutput"><span class="identifier">K</span></code>
        is called <code class="computeroutput"><span class="identifier">key_type</span></code>. It allows
        to select key-value pairs pairs via <code class="computeroutpu