title: std::vector size in header
body: <p>I have small question about std::vector. In main.h i try to make fixed size int vector</p>
  
  <pre><code>std::vector&lt;int&gt; foo(7);
  </code></pre>
  
  <p>But g++ gived this error:</p>
  
  <pre><code>../test/main.h:21:26: error: expected identifier before numeric constant
   std::vector&lt;int&gt; foo(7);
  ../main/main.h:21:26: error: expected ',' or '...' before numeric constant
  </code></pre>
  
  <p>How can i create private vector variable of fixed size length? Or should i simply make in constructor </p>
  
  <pre><code>for(int i=0; i&lt;7;i++){
      foo.push_back(0);
  }
  </code></pre>