title: How to seek around a text file in C?
body: <p>Say I have a simple text file.txt: <code>1234567890</code>. I need to edit it inserting a <code>+</code> between each character in file. Simpliest would be to use <a href="http://www.cplusplus.com/reference/cstdio/fseek/" rel="nofollow">fseek</a> yet </p>
  
  <blockquote>
    <p>For streams open in text mode, offset shall either be zero or a value
    returned by a previous call to ftell, and origin shall necessarily be
    SEEK_SET.</p>
  </blockquote>
  
  <p>So I can only stay where I currently am with it or at the beggining of file stream?</p>
  
  <p>so the question is how to fseek 1 character left or right from current position when editing a text file in C?</p>