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<H2>logical_not</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 unary function object that returns <SAMP>true</SAMP> if its argument is <SAMP>false</SAMP></P>
<A NAME="sec3"><H3>Synopsis</H3></A>

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

namespace std {
  template &lt;class T&gt;
  struct logical_not;
}
</PRE>
<A NAME="sec4"><H3>Description</H3></A>
<P><B><I>logical_not</I></B> is a unary function object. Its <SAMP>operator()</SAMP> returns <SAMP>true</SAMP> if its argument is <SAMP>false</SAMP>. You can pass a <B><I>logical_not</I></B> object to any algorithm that requires a unary function. For example, the <SAMP><A HREF="replace-if.html">replace_if()</A></SAMP> algorithm replaces an element with another value if the result of a unary operation is <SAMP>true</SAMP>. <B><I>logical_not</I></B> is used in that algorithm in the following manner:</P>

<UL><PRE>vector&lt;int&gt; vec1;
.
.
.
void replace_if(vec1.begin(), vec1.end(),
                logical_not&lt;int&gt;(),1);
</PRE></UL>
<P>This call to <SAMP><A HREF="replace-if.html">replace_if()</A></SAMP> replaces all zeros in the <SAMP>vec1</SAMP> with <SAMP>1</SAMP>.</P>
<A NAME="sec5"><H3>Interface</H3></A>

<UL><PRE>namespace std {

  template &lt;class T&gt;
  struct logical_not : unary_function&lt;T, bool&gt; {
    bool operator() (const T&amp;) const;
  };
}
</PRE></UL>
<A NAME="sec6"><H3>See Also</H3></A>
<P><A HREF="functionobjects.html">Function Objects</A>, <B><I><A HREF="unary-function.html">unary_function</A></I></B></P>
<A NAME="sec7"><H3>Standards Conformance</H3></A>
<P><I>ISO/IEC 14882:1998 -- International Standard for Information Systems -- Programming Language C++, Section 20.3.4</I></P>

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