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| <H2>logical_or</H2> |
| <P><B>Library:</B> <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 either of its arguments are <SAMP>true</SAMP></P> |
| <A NAME="sec3"><H3>Synopsis</H3></A> |
| |
| <PRE>#include <functional> |
| |
| namespace std { |
| template <class T> |
| struct logical_or; |
| } |
| </PRE> |
| <A NAME="sec4"><H3>Description</H3></A> |
| <P><B><I>logical_or</I></B> is a binary function object. Its <SAMP>operator()</SAMP> returns <SAMP>true</SAMP> if either <SAMP>x</SAMP> or <SAMP>y</SAMP> are <SAMP>true</SAMP>. You can pass a <B><I>logical_or</I></B> object to any algorithm that requires a binary function. For example, the <SAMP><A HREF="transform.html">transform()</A></SAMP> algorithm applies a binary operation to corresponding values in two collections and stores the result of the function. <B><I>logical_or</I></B> is used in that algorithm in the following manner:</P> |
| |
| <UL><PRE> |
| list<bool> list1; |
| list<bool> list2; |
| list<bool> listResult; |
| . |
| . |
| . |
| transform(list1.begin(), list1.end(), |
| list2.begin(), |
| listResult.begin(), <B>logical_or<bool>()</B>); |
| </PRE></UL> |
| <P>After this call to <SAMP><A HREF="transform.html">transform()</A></SAMP>, <SAMP>listResult(n)</SAMP> contains a <SAMP>1</SAMP> (<SAMP>true</SAMP>) if either <SAMP>list1(n)</SAMP> or <SAMP>list2(n)</SAMP> is <SAMP>true</SAMP>, or a <SAMP>0</SAMP> (<SAMP>false</SAMP>) if both <SAMP>list1(n)</SAMP> and <SAMP>list2(n)</SAMP> are <SAMP>false</SAMP>.</P> |
| <A NAME="sec5"><H3>Interface</H3></A> |
| |
| <UL><PRE>namespace std { |
| |
| template <class T> |
| struct logical_or : binary_function<T, T, bool> { |
| bool operator()(const T&, const T&) 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 20.3.4</I></P> |
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