title: 2-d array in c++
body: <pre><code>vector&lt; vector&lt;int&gt; &gt; vI2Matrix(3, vector&lt;int&gt;(2,0));
  </code></pre>
  
  <p>I know it  declares size of two dimensional array and initializes it. But waht does (2,0 ) means?
  is there any necessary to put it here?
  thanks</p>
  
  <p>When I delete (2,0) or change it to other value. The compilation is right but I got runtime segmentation fault after that.</p>