title: C write in the middle of a binary file without overwriting any existing content
body: <p>Today's problem is that I need to write an array of numbers in a binary file at a starting position. I have the position where it should start, and I don't want to overwrite values after that, just want to insert the array at the starting position in the file. E.g:</p>
  
  <pre><code>12345
  </code></pre>
  
  <p>Let's push 456 at position 2:</p>
  
  <pre><code>12456345
  </code></pre>
  
  <p>I know that probably I'll have to implement it by myself, but I want to know what's your opinion on how to implement that as efficiently as possible.</p>