&gt; Swift gives up on the idea that len(x+y) = len(x) + len(y). This is just something you have to remember; in UI programming, however, it makes a lot of sense because adding an accent to an existing string isn&#x27;t going to make it take up more width in the text box. (x + y).utf8.count == x.utf8.count + y.utf8.count, however.<p>So do fullwidth characters have a length of 2?<p>If not, how is this useful for finding the size of text in a text box anyway?