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.
108 lines
4.4 KiB
HTML
108 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 - Sizeof </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>sizeof</h2>
|
|
<h4>Description</h4>
|
|
<p>The sizeof operator returns the number of bytes in a variable type, or the number of bytes occupied by an array.
|
|
</p>
|
|
<p class='vspace'></p><h4>Syntax</h4>
|
|
<p>sizeof(variable)
|
|
</p>
|
|
<p class='vspace'></p><h4>Parameters</h4>
|
|
<p>variable: any variable type or array (e.g. int, float, byte)
|
|
</p>
|
|
<p class='vspace'></p><h4>Example code</h4>
|
|
<p>The sizeof operator is useful for dealing with arrays (such as strings) where it is convenient to be able to change the size of the array without breaking other parts of the program.
|
|
</p>
|
|
<p class='vspace'></p><p>This program prints out a text string one character at a time. Try changing the text phrase.
|
|
</p>
|
|
<p class='vspace'></p><pre>
|
|
char myStr[] = "this is a test";
|
|
int i;
|
|
|
|
void setup(){
|
|
Serial.begin(9600);
|
|
}
|
|
|
|
void loop() {
|
|
for (i = 0; i < sizeof(myStr) - 1; i++){
|
|
Serial.print(i, DEC);
|
|
Serial.print(" = ");
|
|
Serial.println(myStr[i], BYTE);
|
|
}
|
|
}
|
|
|
|
|
|
</pre><p>Note that sizeof returns the total number of bytes. So for larger variable types such as ints, the for loop would look something like this.
|
|
</p>
|
|
<p class='vspace'></p><pre>
|
|
for (i = 0; i < (sizeof(myInts)/sizeof(int)) - 1; i++) {
|
|
// do something with myInts[i]
|
|
}
|
|
|
|
</pre>
|
|
<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>
|