title: Why the absolute value of the max negative integer -2147483648 is still -2147483648?
body: <p>The result of abs(-2147483648) is -2147483648, isn't it?
  it seems unacceptable.</p>
  
  <pre><code>printf("abs(-2147483648): %d\n", abs(-2147483648));
  </code></pre>
  
  <p>output:</p>
  
  <pre><code>abs(-2147483648): -2147483648
  </code></pre>