title: ASCII char to int conversions in C
body: <blockquote>
    <p><strong>Possible Duplicate:</strong><br>
    <a href="https://stackoverflow.com/questions/781668/char-to-int-conversion-in-c">Char to int conversion in C.</a>  </p>
  </blockquote>
  
  
  
  <p>I remember learning in a course a long time ago that converting from an ASCII char to an int by subtracting '0' is bad.</p>
  
  <p>For example:</p>
  
  <pre><code>int converted;
  char ascii = '8';
  
  converted = ascii - '0';
  </code></pre>
  
  <p>Why is this considered a bad practice? Is it because some systems don't use ASCII? The question has been bugging me for a long time.</p>