You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
85 lines
4.4 KiB
HTML
85 lines
4.4 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
|
|
<html>
|
|
<head>
|
|
<title>Arduino - BitwiseXorNot </title>
|
|
<link rel='stylesheet' href='arduino.css' type='text/css' />
|
|
<meta name="verify-v1" content="TtxFIEJAB6zdJ509wLxjnapQzKAMNm9u0Wj4ho6wxIY=" />
|
|
</head>
|
|
<body>
|
|
<div id="page">
|
|
<!--PageHeaderFmt-->
|
|
<div id="pageheader">
|
|
<div class="title"><a href="http://www.arduino.cc"/>Arduino</a></div>
|
|
<div class="search">
|
|
<!-- SiteSearch Google -->
|
|
<FORM method=GET action="http://www.google.com/search">
|
|
<input type=hidden name=ie value=UTF-8>
|
|
<input type=hidden name=oe value=UTF-8>
|
|
<INPUT TYPE=text name=q size=25 maxlength=255 value="">
|
|
<INPUT type=submit name=btnG VALUE="search">
|
|
<input type=hidden name=domains value="http://www.arduino.cc/">
|
|
<input type=hidden name=sitesearch value="http://www.arduino.cc/">
|
|
</FORM>
|
|
<!-- SiteSearch Google -->
|
|
</div>
|
|
</div>
|
|
<!--/PageHeaderFmt-->
|
|
<!--PageLeftFmt-->
|
|
<div id="pagenav" style="text-align: right">
|
|
<div style="float: left;">
|
|
<p><a class='wikilink' href='http://arduino.cc/en/Main/Buy'>Buy</a>
|
|
|
|
|
<a class='wikilink' href='http://arduino.cc/en/Main/Software'>Download</a>
|
|
|
|
|
<a class='wikilink' href='Guide_index.html'>Getting Started</a>
|
|
|
|
|
<a class='wikilink' href='http://arduino.cc/en/Tutorial/HomePage'>Learning</a>
|
|
|
|
|
<a class='wikilink' href='index.html'>Reference</a>
|
|
|
|
|
<a class='wikilink' href='http://arduino.cc/en/Main/Hardware'>Hardware</a>
|
|
|
|
|
<a class='wikilink' href='FAQ.html'>FAQ</a>
|
|
</p>
|
|
<p class='vspace'></p>
|
|
|
|
</div>
|
|
<a class="urllink" href="http://www.arduino.cc/blog/" rel="nofollow">Blog »</a> |
|
|
<a class="urllink" href="http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl" rel="nofollow">Forum »</a> |
|
|
<a class="urllink" href="http://www.arduino.cc/playground/" rel="nofollow">Playground »</a>
|
|
</div>
|
|
<!--/PageLeftFmt-->
|
|
<div id="pagetext">
|
|
<!--PageText-->
|
|
<div id='wikitext'>
|
|
<p><strong>Reference</strong> <a class='wikilink' href='index.html'>Language</a> (<a class='wikilink' href='Extended.html'>extended</a>) | <a class='wikilink' href='Libraries.html'>Libraries</a> | <a class='wikilink' href='Comparison.html'>Comparison</a> | <a class='wikilink' href='Changes.html'>Changes</a>
|
|
</p>
|
|
<p class='vspace'></p><h2>Bitwise NOT (~)</h2>
|
|
<p>The bitwise NOT operator in C++ is the tilde character ~. Unlike & and |, the bitwise NOT operator is applied to a single operand to its right. Bitwise NOT changes each bit to its opposite: 0 becomes 1, and 1 becomes 0. For example:
|
|
</p>
|
|
<p class='vspace'></p><pre> 0 1 operand1
|
|
</pre>
|
|
<p class='vspace'></p><pre> ----------
|
|
1 0 ~ operand1
|
|
</pre>
|
|
<p class='vspace'></p><pre> int a = 103; // binary: 0000000001100111
|
|
int b = ~a; // binary: 1111111110011000 = -104
|
|
</pre>
|
|
<p class='vspace'></p><p>You might be surprised to see a negative number like -104 as the result of this operation. This is because the highest bit in an int variable is the so-called sign bit. If the highest bit is 1, the number is interpreted as negative. This encoding of positive and negative numbers is referred to as two's complement. For more information, see the Wikipedia article on <a class='urllink' href='http://en.wikipedia.org/wiki/Twos_complement' rel='nofollow'>two's complement.</a>
|
|
</p>
|
|
<p class='vspace'></p><p>As an aside, it is interesting to note that for any integer x, ~x is the same as -x-1.
|
|
</p>
|
|
<p class='vspace'></p><p>At times, the sign bit in a signed integer expression can cause some unwanted surprises.
|
|
</p>
|
|
<p class='vspace'></p><p><a class='wikilink' href='index.html'>Reference Home</a>
|
|
</p>
|
|
<p class='vspace'></p><p><em>Corrections, suggestions, and new documentation should be posted to the <a class='urllink' href='http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?board=swbugs' rel='nofollow'>Forum</a>.</em>
|
|
</p>
|
|
<p class='vspace'></p><p>The text of the Arduino reference is licensed under a
|
|
<a class='urllink' href='http://creativecommons.org/licenses/by-sa/3.0/' rel='nofollow'>Creative Commons Attribution-ShareAlike 3.0 License</a>. Code samples in the reference are released into the public domain.
|
|
</p>
|
|
</div>
|
|
|
|
</div>
|
|
<!--PageFooterFmt-->
|
|
<div id="pagefooter">
|
|
<a href='#'>Edit Page</a> | <a href='#'>Page History</a> | <a href='#' target='_blank'>Printable View</a> | <a href='http://arduino.cc/en/Site/AllRecentChanges'>All Recent Site Changes</a>
|
|
</div>
|
|
<!--/PageFooterFmt-->
|
|
</div>
|
|
</body>
|
|
</html>
|