String Trim Comparison between pointer and integer
<p>I need to check whether the incoming string is not null and not empty</p>

<pre><code>method(const char* utf8char){
</code></pre>

<p>....</p>

<pre><code>string trim(char const *str){
    while(!isalnum(*str)) str++;
    end = str + strlen(str) - 1;
    while(end &gt; str &amp;&amp; !isalnum(*end)) end--;
    return string(str, end+1);
}
</code></pre>

<p><strong>warning: comparison between pointer and integer</strong></p>

<p>Sorry for dumb question I am novice in C++.</p>
