title: fastest way to negate a number
body: <p>I was thinking this morning here, what would be the fastest way to reverse a number of positive to negative and from negative to positive, of course, the simplest way might be:</p>
  
  <pre><code>int a = 10;
  a = a*(-1);
  </code></pre>
  
  <p>or</p>
  
  <pre><code>int a = 10;
  a = -a;
  </code></pre>
  
  <p>But then, I thought, I take that to do this, using commands shift and pointers ...
  That really would be possible to change the sign of a value, using commands shift operators and memory?</p>