title: reading bytes from binary file to long int
body: <p>I have two question :</p>
  
  <ul>
  <li><p>I have a data on binary file. I want read first 8 bytes to signed long int by using read function but I could not .  Do you know how can I do that ? </p></li>
  <li><p>How can directly read a block of data to string ?
  Can I read like as shown in 
  ex : </p>
  
  <pre><code> ifstream is;
   is.open ("test.txt", ios::binary );
  
   string str ;
   is. read ( str.c_str, 40 ) ; // 40 bytes should be read
  </code></pre></li>
  </ul>