title: Make an int vector receive the values from a vector of a class that has an int
body: <p>So, suppose I have this:</p>
  
  <pre><code>...
  struct circle {
     int radius;
     char color;   
  }    
  
  vector&lt;circle&gt; circles; 
  ...
  
  vector&lt;int&gt; sizes;    
  for (int i = 0; i &lt; circles.size(); i++) {
      sizes[i] = circles[i].radius;
  }
  ...
  </code></pre>
  
  <p>is there a way of making "sizes" receive automatically all "radius" without the "for" routine?</p>
  
  <p>Thanks in advance.</p>