title: How to set a string to all lowercase
body: <p>I have a <code>char foo[SIZE]; //(string)</code> </p>
  
  <p>and have inputed it correctly using <code>%s</code> (as in it <code>printfs</code> the correct input), but now want to set it to lowercase. So I tried using </p>
  
  <pre><code> if (isupper(*foo)) 
     *foo=tolower(*foo); 
  </code></pre>
  
  <p>ie when I do:</p>
  
  <pre><code>printf("%s" foo); //I get the same text with upper case
  </code></pre>
  
  <p>The text does not seem to change. Thank you. </p>