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.
99 lines
4.9 KiB
HTML
99 lines
4.9 KiB
HTML
15 years ago
|
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
|
||
|
|
<html>
|
||
|
|
<head>
|
||
|
|
<title>Arduino - Float </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>float</h2>
|
||
|
|
<h4>Description </h4>
|
||
|
|
<p>Datatype for floating-point numbers, a number that has a decimal point. Floating-point numbers are often used to approximate analog and continuous values because they have greater resolution than integers. Floating-point numbers can be as large as 3.4028235E+38 and as low as -3.4028235E+38. They are stored as 32 bits (4 bytes) of information.
|
||
|
|
</p>
|
||
|
|
<p class='vspace'></p><p>Floating point numbers are not exact, and may yield strange results when compared. For example <code>6.0 / 3.0</code> may not equal <code>2.0</code>. You should instead check that the absolute value of the difference between the numbers is less than some small number.
|
||
|
|
</p>
|
||
|
|
<p class='vspace'></p><p>Floating point math is also much slower than integer math in performing calculations, so should be avoided if, for example, a loop has to run at top speed for a critical timing function. Programmers often go to some lengths to convert floating point calculations to integer math to increase speed.
|
||
|
|
</p>
|
||
|
|
<p class='vspace'></p><h4>Examples</h4>
|
||
|
|
<pre> float myfloat;
|
||
|
|
float sensorCalbrate = 1.117;
|
||
|
|
</pre>
|
||
|
|
<p class='vspace'></p><h4>Syntax</h4>
|
||
|
|
<pre> float var = val;
|
||
|
|
</pre>
|
||
|
|
<p class='vspace'></p><ul><li>var - your float variable name
|
||
|
|
</li><li>val - the value you assign to that variable
|
||
|
|
</li></ul><p class='vspace'></p><h4>Example Code</h4>
|
||
|
|
<pre>
|
||
|
|
int x;
|
||
|
|
int y;
|
||
|
|
float z;
|
||
|
|
|
||
|
|
x = 1;
|
||
|
|
y = x / 2; // y now contains 0, ints can't hold fractions
|
||
|
|
z = (float)x / 2.0; // z now contains .5 (you have to use 2.0, not 2)
|
||
|
|
</pre>
|
||
|
|
<p class='vspace'></p><h4>See Also</h4>
|
||
|
|
<ul><li><a class='wikilink' href='Int.html'>int</a>
|
||
|
|
</li><li><a class='wikilink' href='Double.html'>double</a>
|
||
|
|
</li><li><a class='urllink' href='VariableDeclaration.html' rel='nofollow'>Variable Declaration</a>
|
||
|
|
</li></ul><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>
|