title: What does signed and unsigned values mean?
body: <p>What does <code>signed</code> mean in C? I have this table to show:</p>
  
  <p><img src="https://i.stack.imgur.com/MWnZI.jpg" alt="enter image description here"></p>
  
  <p>This says <code>signed char</code> <code>128</code> to <code>+127</code>. <code>128</code> is also a positive integer, so how can this be something like <code>+128</code> to <code>+127</code>? Or do <code>128</code> and <code>+127</code> have different meanings? I am referring to the book Apress <a href="http://www.apress.com/9781590597354" rel="noreferrer">Beginning C</a>.</p>