title: Is slicing a vector faster than copying each element into a new vector?
body: <p>Let's say I have a vector of 10 ints and I want to create 2 subvectors each of 5 elements.</p>
  <p>Is it faster if I slice the vector like this:</p>
  <pre><code>vector&lt;int&gt; vec({0,1,2,3,4,5,6,7,8,9});
  auto x = vec.begin();
  vector&lt;int&gt; vec2(x, x+5);
  x += 5;
  vector&lt;int&gt; vec3(x, x+5);
  </code></pre>
  <p>As opposed to this?</p>
  <pre><code>vector&lt;int&gt; vec({0,1,2,3,4,5,6,7,8,9});
  vector&lt;int&gt; vec2;
  for (int i = 0; i &lt; 5; i++) {
      vec2.push_back(vec[i]);
  }
  vector&lt;int&gt; vec3;
  for (int i = 5; i &lt; 10; i++) {
      vec3.push_back(vec[i]);
  }
  </code></pre>