title: Why my C program is failed to detect the special characters?
body: <p>I have written a C program to detect input types. It detects alphabets and digits well but it is detecting special characters as digits. Please help me to solve the question.
  Code:</p>
  
  <pre><code>#include &lt;stdio.h&gt;
  int main()
  {
      char c;
      scanf("%c", &amp;c);
      if (c &gt;= 'a' &amp;&amp; c &lt;= 'z') printf("Alphabet of lower case.");
      else if (c &gt;= 'A' &amp;&amp; c &lt;= 'Z') printf("Alphabet of upper case.");
      else if (c &gt;= 0 || c &lt; 0) printf("Digit");
      else printf("Special character.");
      return 0;
  }
  
  </code></pre>
  
  <p>Output of this program:</p>
  
  <p><img src="https://i.stack.imgur.com/9zp4r.png" alt="enter image description here"></p>