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<H2>equal_to</H2>
<P><B>Library:</B>&nbsp;&nbsp;<A HREF="2-4.html">General utilities</A></P>

<PRE><HR><B><I>Does not inherit</I></B><HR></PRE>

<UL>
<LI><A HREF="#sec1">Local Index</A></LI>
<LI><A HREF="#sec2">Summary</A></LI>
<LI><A HREF="#sec3">Synopsis</A></LI>
<LI><A HREF="#sec4">Description</A></LI>
<LI><A HREF="#sec5">Interface</A></LI>
<LI><A HREF="#sec6">See Also</A></LI>
<LI><A HREF="#sec7">Standards Conformance</A></LI>
</UL>
<A NAME="sec1"><H3>Local Index</H3></A>
No Entries
<A NAME="sec2"><H3>Summary</H3></A>
<P>A binary function object that returns <SAMP>true</SAMP> if its first argument equals its second</P>
<A NAME="sec3"><H3>Synopsis</H3></A>

<PRE>#include &lt;functional&gt;

namespace std {
  template &lt;class T&gt;
  struct equal_to;
}
</PRE>
<A NAME="sec4"><H3>Description</H3></A>
<P><B><I>equal_to</I></B> is a binary function object. Its <SAMP>operator()</SAMP> returns <SAMP>true</SAMP> if <SAMP>x</SAMP> is equal to <SAMP>y</SAMP>. You can pass an <B><I>equal_to</I></B> object to any algorithm that requires a binary function. For example, the <SAMP><A HREF="find-if.html">find_if()</A></SAMP> algorithm finds the first occurrence of any value from one sequence in another sequence as determined by applying a binary comparison operation. <B><I>equal_to</I></B> would be used in that algorithm in the following manner:</P>

<UL><PRE>
vector&lt;int&gt; vec1;
vector&lt;int&gt; vec2;
vector&lt;int&gt;::iterator iter1;
.
.
.
iter1 = find_if(vec1.begin(), vec1.end(),
                vec2.begin(), vec2.end(), <B>equal_to</B>&lt;int&gt;());
</PRE></UL>
<P>After this call to <SAMP><A HREF="find-if.html">find_if()</A></SAMP>, <SAMP>iter1</SAMP> points to the first element in <SAMP>vec1</SAMP> for which <SAMP>equal_to(vec1[n],vec2[n])</SAMP> returned <SAMP>true</SAMP>; or, if there were no matches, <SAMP>iter1</SAMP> points to <SAMP>vec2.end()</SAMP>.</P>
<A NAME="sec5"><H3>Interface</H3></A>

<UL><PRE>namespace std {
  template &lt;class T&gt;
  struct equal_to : binary_function&lt;T, T, bool&gt; { 
    bool operator()(const T&amp; x, const T&amp; y) const;
  }; 
}
</PRE></UL>
<A NAME="sec6"><H3>See Also</H3></A>
<P><B><I><A HREF="binary-function.html">binary_function</A></I></B>, <A HREF="functionobjects.html">Function Objects</A></P>
<A NAME="sec7"><H3>Standards Conformance</H3></A>
<P><I>ISO/IEC 14882:1998 -- International Standard for Information Systems -- Programming Language C++, Section 20.3.3</I></P>

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