title: strcat not working when trying to add a string and a char?
body: <p>One of the first times I'm using C. I can't append the string every time I encounter a capital letter. I understand that this is very simple in most languages but I am trying to learn it in C.</p>
  
  <pre><code>string s = get_string();
  string s1 = "";
  
  for (int i = 0, n = strlen(s); i &lt; n; i++)
  {
      if (s[i] &gt;= 'A' &amp;&amp; s[i] &lt;= 'Z')
      {
          strcat (s1,s[i]);
      }
  }
  </code></pre>