title: Read number from text file using C++ stream
body: <p>I have a text file like below</p>
  
  <pre><code>2 1 2
  5 10 13 11 12 14
  2 0 1
  2 99 2
  200 2
  1 5
  5 1 2 3 4 5
  1 0
  0 0
  </code></pre>
  
  <p>I want to read file line by line, and read the umbers from each line. I know how to use the stream to read a fixed field line, but what about the non-fixed line?</p>
  
  <p>Best Regards,</p>