title: Construct an empty matrix
body: <p>I have a class </p>
  
  <pre><code>class A
  {
      int *const e;
      const int row, column;
  public:
      A(int r, int c); // create a empty matrix with r rows and c columns passed in method
  }
  
  int main(int argc, char* argv[])
  {
      A test(2,2); 
      return 0;
  }
  </code></pre>
  
  <p>Question is how can I write a constructor that create a matrix which I can use ?    </p>