title: Which is faster, multiplication or subtraction?
body: <p>I'm currently doing a University project which is marked heavily upon the speed and efficiency of my solution. Minor changes I make to the code have massive impacts, as the particular function I am writing is called many hundreds of thousands of times.</p>
  
  <p>I have written the main functionality of my project now, and am currently in the process of optimising everything I possibly can. One particular part of my code that I am questioning looks like this:</p>
  
  <pre><code>array[i] *= -1;
  </code></pre>
  
  <p>Which I was considering optimising to:</p>
  
  <pre><code>array[i] = 0 - array[i];
  </code></pre>
  
  <p>Would changing this code actually affect the speed? Is a subtraction operation faster than a multiplication operation? Or is this kind of issue a thing of the past?</p>