title: C++ Regarding unsigned long long
body: <p>Why does (unsigned long long) -1 = 18446744073709551615. Is there anyway to ensure -1 stays -1 ? As I am currently picking up C++, I'm new. </p>
  
  <pre><code>unsigned long long a = -1;
  cout &lt;&lt; a &lt;&lt; endl;
  cout &lt;&lt; (a &gt;= 0) &lt;&lt; endl;  //This returns 1 which is what I don't understand. 1 is 
                             //true for C++ right?
  </code></pre>