title: C - distance between 2 pointers
body: <p>How can I know the distance in bytes between 2 pointers?
  For example:
  <img src="https://i.stack.imgur.com/z2e6q.png" alt="Distance between p1 and p2"></p>
  
  <p>I would like to know how many bytes there are between p2 and p1 ( in this case 3) because to reach p2 with p1 I have to do 3 steps...<br>
  <strong>step1 p1 is in B<br>
  step2 p1 is in C<br>
  step3 p1 is in D</strong><br></p>
  
  <p><strong>so i need that return to me 3</strong><br>
  I'm asking this type of question because I'm implementing the lz77 algorithm</p>