mirror of
https://github.com/arduino/Arduino.git
synced 2024-12-12 23:08:52 +01:00
124 lines
5.6 KiB
HTML
124 lines
5.6 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 Reference - Arithmetic </title>
|
|
<link rel="shortcut icon" type="image/x-icon" href="http://arduino.cc/en/favicon.png">
|
|
<link rel='stylesheet' href='arduinoWideRender.css'
|
|
type='text/css' />
|
|
<!--HeaderText--><style type='text/css'><!--
|
|
ul, ol, pre, dl, p { margin-top:0px; margin-bottom:0px; }
|
|
code { white-space: nowrap; }
|
|
.vspace { margin-top:1.33em; }
|
|
.indent { margin-left:40px; }
|
|
.outdent { margin-left:40px; text-indent:-40px; }
|
|
a.createlinktext { text-decoration:none; border-bottom:1px dotted gray; }
|
|
a.createlink { text-decoration:none; position:relative; top:-0.5em;
|
|
font-weight:bold; font-size:smaller; border-bottom:none; }
|
|
img { border:0px; }
|
|
.editconflict { color:green;
|
|
font-style:italic; margin-top:1.33em; margin-bottom:1.33em; }
|
|
|
|
table.markup { border: 2px dotted #ccf; width:90%; }
|
|
td.markup1, td.markup2 { padding-left:10px; padding-right:10px; }
|
|
td.markup1 { border-bottom: 1px solid #ccf; }
|
|
div.faq { margin-left:2em; }
|
|
div.faq p.question { margin: 1em 0 0.75em -2em; font-weight:bold; }
|
|
div.faq hr { margin-left: -2em; }
|
|
|
|
.frame
|
|
{ border:1px solid #cccccc; padding:4px; background-color:#f9f9f9; }
|
|
.lfloat { float:left; margin-right:0.5em; }
|
|
.rfloat { float:right; margin-left:0.5em; }
|
|
a.varlink { text-decoration:none; }
|
|
|
|
--></style> <meta name='robots' content='index,follow' />
|
|
|
|
<meta name="verify-v1" content="TtxFIEJAB6zdJ509wLxjnapQzKAMNm9u0Wj4ho6wxIY=" />
|
|
</head>
|
|
<body>
|
|
<div id="page">
|
|
<!--PageHeaderFmt-->
|
|
<div id="pageheader">
|
|
<div class="title"><a href='http://arduino.cc/en'>Arduino</a></div>
|
|
</div>
|
|
<!--/PageHeaderFmt-->
|
|
|
|
<!--PageLeftFmt-->
|
|
<div id="pagenav">
|
|
<div id="navbar">
|
|
<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>
|
|
</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='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>Addition, Subtraction, Multiplication, & Division</h2>
|
|
<h4>Description</h4>
|
|
<p>These operators return the sum, difference, product, or quotient (respectively) of the two operands. The operation is conducted using the data type of the operands, so, for example, <code>9 / 4</code> gives <code>2</code> since 9 and 4 are ints. This also means that the operation can overflow if the result is larger than that which can be stored in the data type (e.g. adding 1 to an <a class='wikilink' href='Int.html'>int</a> with the value 32,767 gives -32,768). If the operands are of different types, the "larger" type is used for the calculation.
|
|
</p>
|
|
<p class='vspace'></p><p>If one of the numbers (operands) are of the type <strong>float</strong> or of type <strong>double</strong>, floating point math will be used for the calculation.
|
|
</p>
|
|
<p class='vspace'></p><h4>Examples</h4>
|
|
<pre>
|
|
y = y + 3;
|
|
x = x - 7;
|
|
i = j * 6;
|
|
r = r / 5;
|
|
|
|
</pre>
|
|
<p class='vspace'></p><h4>Syntax</h4>
|
|
<pre>
|
|
result = value1 + value2;
|
|
result = value1 - value2;
|
|
result = value1 * value2;
|
|
result = value1 / value2;
|
|
|
|
</pre>
|
|
<p class='vspace'></p><h4>Parameters:</h4>
|
|
<p>value1: any variable or constant
|
|
</p>
|
|
<p class='vspace'></p><p>value2: any variable or constant
|
|
</p>
|
|
<p class='vspace'></p><h4>Programming Tips:</h4>
|
|
<ul><li>Know that <a class='wikilink' href='IntegerConstants.html'>integer constants</a> default to <a class='wikilink' href='Int.html'>int</a>, so some constant calculations may overflow (e.g. 60 * 1000 will yield a negative result).
|
|
<p class='vspace'></p></li><li>Choose variable sizes that are large enough to hold the largest results from your calculations
|
|
<p class='vspace'></p></li><li>Know at what point your variable will "roll over" and also what happens in the other direction e.g. (0 - 1) OR (0 - - 32768)
|
|
<p class='vspace'></p></li><li>For math that requires fractions, use float variables, but be aware of their drawbacks: large size, slow computation speeds
|
|
<p class='vspace'></p></li><li>Use the cast operator e.g. (int)myFloat to convert one variable type to another on the fly.
|
|
</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://arduino.cc/forum/index.php/board,23.0.html' 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">
|
|
©Arduino |
|
|
<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>
|