title: using push_back to put a vector<double> into a vector<vector<double>>
body: <p>I have a <code>std::vector&lt;vector&lt;double&gt;&gt;</code> I want to fill in one function.
  I need to store some 3 dimensional coordinates for some calculations later in my program.</p>
  
  <p>My Question is if I do this:</p>
  
  <pre><code>//in classdefinition
  std::vector&lt;std::vector&lt;double&gt;&gt; data;
  
      myFunc()
      {
          std::vector&lt;double&gt; temp;
          temp.push_back(1);
          temp.push_back(2);
          temp.push_back(3);
          data.push_back(temp);
  
          temp.clear();
          //new data
          temp.push_back(2);
          temp.push_back(3);
          temp.push_back(4);
          data.push_back(temp);
      }
  </code></pre>
  
  <p>will the clearing and refilling of temp influence the values in data?</p>
  
  <p>I already found this <a href="http://www.cplusplus.com/reference/vector/vector/push_back/" rel="nofollow">http://www.cplusplus.com/reference/vector/vector/push_back/</a>
  but since the explanation reads "The content of val is copied (or moved) to the new element." I don't know what to think. To me this sounds like a contradiction.</p>
  
  <p>I think it would not make much sense if the variables are passed as a reference since they can, like in my case, only be valid in a limited scope.
  Am I right with my assumption?</p>