title: Why has the int32 type a maximum value of 2³¹ − 1?
body: <blockquote>
  <p><strong>Possible Duplicate:</strong><br />
  <a href="https://stackoverflow.com/questions/1049722/2s-complement-defined">What is &quot;2's Complement&quot;?</a></p>
  </blockquote>
  
  <p>I know int32 has a length of 32 bits (4 bytes). I assume it has 2³² values but as half of them must be under zero, I guess it has something to do with this.
  I would like to know why exactly int32 has max. positive number 2³¹ − 1.</p>