<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en"
lang="en" dir="ltr">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>
find_first_of [C++ Reference]
</title>
<meta name="generator" content="DokuWiki Release 2009-12-25c "Lemming"" />
<meta name="robots" content="index,follow" />
<meta name="date" content="2009-10-10T20:07:50-0700" />
<meta name="keywords" content="string,find_first_of" />
<link rel="search" type="application/opensearchdescription+xml" href="/wiki/lib/exe/opensearch.php" title="C++ Reference" />
<link rel="start" href="/wiki/" />
<link rel="contents" href="/wiki/string/find_first_of?do=index" title="Index" />
<link rel="alternate" type="application/rss+xml" title="Recent Changes" href="/wiki/feed.php" />
<link rel="alternate" type="application/rss+xml" title="Current Namespace" href="/wiki/feed.php?mode=list&ns=string" />
<link rel="edit" title="Edit this page" href="/wiki/string/find_first_of?do=edit" />
<link rel="alternate" type="text/html" title="Plain HTML" href="/wiki/_export/xhtml/string/find_first_of" />
<link rel="alternate" type="text/plain" title="Wiki Markup" href="/wiki/_export/raw/string/find_first_of" />
<link rel="canonical" href="http://www.cppreference.com/wiki/string/find_first_of" />
<link rel="stylesheet" media="all" type="text/css" href="/wiki/lib/exe/css.php?s=all&t=custom1&tseed=1272971091" />
<link rel="stylesheet" media="screen" type="text/css" href="/wiki/lib/exe/css.php?t=custom1&tseed=1272971091" />
<link rel="stylesheet" media="print" type="text/css" href="/wiki/lib/exe/css.php?s=print&t=custom1&tseed=1272971091" />
<script type="text/javascript" charset="utf-8" ><!--//--><![CDATA[//><!--
var NS='string';var JSINFO = {"id":"string:find_first_of","namespace":"string"};
//--><!]]></script>
<script type="text/javascript" charset="utf-8" src="/wiki/lib/exe/js.php?tseed=1272971091" ></script>
<link rel="shortcut icon" href="/wiki/lib/tpl/custom1/images/favicon.png" />
</head>
<body>
<div class="dokuwiki">
<div class="stylehead">
<div class="breadcrumbs">
<span class="bchead">You are here: </span><a href="../start.html" title="start">C++ Reference</a> » <a href="../string/start.html" title="string:start">C++ Strings</a> » <a href="../string/find_first_of.html" title="string:find_first_of">find_first_of</a> </div>
</div>
<div class="page">
<script src="http://www.google-analytics.com/urchin.js" type="text/javascript">
</script>
<script type="text/javascript">
_uacct = "UA-2828341-1";
urchinTracker();
</script>
<!-- wikipage start -->
<h2><a name="find_first_of" id="find_first_of">find_first_of</a></h2>
<div class="level2">
<p>
Syntax:
</p>
<pre class="c code c++" style="font-family:monospace;"> <span class="co2">#include <string></span>
size_type find_first_of<span class="br0">(</span> <span class="kw4">const</span> <span class="kw4">string</span> <span class="sy0">&</span>str<span class="sy0">,</span> size_type index <span class="sy0">=</span> 0 <span class="br0">)</span> <span class="kw4">const</span><span class="sy0">;</span>
size_type find_first_of<span class="br0">(</span> <span class="kw4">const</span> Char<span class="sy0">*</span> str<span class="sy0">,</span> size_type index <span class="sy0">=</span> 0 <span class="br0">)</span> <span class="kw4">const</span><span class="sy0">;</span>
size_type find_first_of<span class="br0">(</span> <span class="kw4">const</span> Char<span class="sy0">*</span> str<span class="sy0">,</span> size_type index<span class="sy0">,</span> size_type num <span class="br0">)</span> <span class="kw4">const</span><span class="sy0">;</span>
size_type find_first_of<span class="br0">(</span> Char ch<span class="sy0">,</span> size_type index <span class="sy0">=</span> 0 <span class="br0">)</span> <span class="kw4">const</span><span class="sy0">;</span></pre>
<p>
The find_first_of function either:
</p>
<ul>
<li class="level1"><div class="li"> returns the index of the first character within the current string that matches any character in <code>str</code>, beginning the search at <code>index</code>, string::npos if nothing is found,</div>
</li>
<li class="level1"><div class="li"> searches the current string, beginning at <code>index</code>, for any of the first <code>num</code> characters in <code>str</code>, returning the index in the current string of the first character found, or string::npos if no characters match,</div>
</li>
<li class="level1"><div class="li"> or returns the index of the first occurrence of <code>ch</code> in the current string, starting the search at <code>index</code>, string::npos if nothing is found.</div>
</li>
</ul>
<p>
For example, the following code uses find_first_of to replace all the vowels in a string with asterisks:
</p>
<pre class="c code c++" style="font-family:monospace;"> <span class="kw4">string</span> str <span class="sy0">=</span> <span class="st0">"In this house, we obey the laws of thermodynamics!"</span><span class="sy0">;</span>
<span class="kw4">string</span><span class="sy0">::</span><span class="me2">size_type</span> found <span class="sy0">=</span> str.<span class="me1">find_first_of</span><span class="br0">(</span><span class="st0">"aeiouAEIOU"</span><span class="br0">)</span><span class="sy0">;</span>
<span class="kw1">while</span><span class="br0">(</span> found <span class="sy0">!=</span> <span class="kw4">string</span><span class="sy0">::</span><span class="me2">npos</span> <span class="br0">)</span> <span class="br0">{</span>
str<span class="br0">[</span>found<span class="br0">]</span> <span class="sy0">=</span> <span class="st0">'*'</span><span class="sy0">;</span>
found <span class="sy0">=</span> str.<span class="me1">find_first_of</span><span class="br0">(</span><span class="st0">"aeiouAEIUO"</span><span class="sy0">,</span>found<span class="sy0">+</span>1<span class="br0">)</span><span class="sy0">;</span>
<span class="br0">}</span>
<a href="http://www.opengroup.org/onlinepubs/009695399/functions/cout.html"><span class="kw3">cout</span></a> <span class="sy0"><<</span> str <span class="sy0"><<</span> <span class="st0">'<span class="es1">\n</span>'</span><span class="sy0">;</span> <span class="co1">// displays "*n th*s h**s*, w* *b*y th* l*ws *f th*rm*dyn*m*cs!"</span></pre>
<p>
Related Topics: <a href="../string/find.html" class="wikilink1" title="string:find">find</a>, <a href="../string/find_first_not_of.html" class="wikilink1" title="string:find_first_not_of">find_first_not_of</a>, <a href="../string/find_last_not_of.html" class="wikilink1" title="string:find_last_not_of">find_last_not_of</a>, <a href="../string/find_last_of.html" class="wikilink1" title="string:find_last_of">find_last_of</a>, <a href="../string/rfind.html" class="wikilink1" title="string:rfind">rfind</a>
</p>
</div>
<!-- wikipage stop -->
</div>
<div class="clearer"> </div>
<div class="stylefoot">
<div class="meta">
<div class="user">
</div>
<!--
<div class="doc">
string/find_first_of.txt · Last modified: 10/10/2009 20:07 by 124.255.102.233 </div>
-->
</div>
</div></div></body>
</html>