title: Check if a char is a digit? (in C)
body: <p><strong>NOTE THAT I AM A NEWBIE</strong></p>
  
  <p>I've used <code>isdigit()</code> function before, but now I have an issue:</p>
  
  <p>I need to check if (for an example) a <code>char</code> with the value <code>-46</code> is a digit. <code>isdigit()</code> doesn`t seem to recognize negative numbers (probably because of that <strong>-</strong> before the actual number). </p>
  
  <p>Is there a simple line of code that can have the same effect as <code>isdigit()</code> function, but that detects negative numbers as well? (like an ASCII table range or something)</p>
  
  <p>Let me clarify myself further: I have an char type array: <code>char A[20]</code> I enter each value manually (example): </p>
  
  <pre><code>A[0]= a
  A[1]= b
  A[2]= -46
  </code></pre>
  
  <p>Now from those 3 (ignore the remaining 17 - this is just an example), I need to check if any of those is a digit. -46 is a number that i`m searching for (to put it in another array), so my question is how do I check if that -46 "is a digit"?</p>