title: print hexadecimal with capital letters
body: <p>I'm trying to print the Unicode value of a wide character like so:</p>
  
  <pre><code>wchar_t w = '\u00A1';   // U+00A1 Inverted Exclamation Mark ¡
  wprintf("U+%.4x",w);    // prints U+00a1
  </code></pre>
  
  <p>I'd like the output to be <code>U+00A1</code> instead of <code>U+00a1</code>. Is there a <code>printf</code> specifier to do this or will I have to do it manually?</p>