title: Vector by referece in constructor: uninitialized reference
body: <p>Uses of vector using namespace is wrong. Might be a typo. Please change as follows.
  Use std::vector
  I have to following code:</p>
  
  <pre><code>class MyClass{
  
  private:
  
  std::vector&lt;float&gt;&amp; myvector;
  
  public:
  
  MyClass(int k,std::vector&lt;float&gt;&amp; vector){
  
  (...)
  
  this-&gt;myvector=vector;
  
  (...)
  
  }
  </code></pre>
  
  <p>I create a MyClass object like this:</p>
  
  <pre><code>(...)
  
  std::vector&lt;float&gt; vector;
  vector.reserve(k);
  
  (...)
  
  MyClass A= MyClass(k,vector);
  
  (...)
  </code></pre>
  
  <p>An error pops out telling me MyVector is an uninitialized reference. I just want MyClass to store some data in MyVector and return it. Should I use pointers instead?.</p>
  
  <p>Thanks</p>