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<HTML><!-- -- Copyright (c) 1996-1999 -- Silicon Graphics Computer Systems, Inc. -- -- Permission to use, copy, modify, distribute and sell this software -- and its documentation for any purpose is hereby granted without fee, -- provided that the above copyright notice appears in all copies and -- that both that copyright notice and this permission notice appear -- in supporting documentation. Silicon Graphics makes no -- representations about the suitability of this software for any -- purpose. It is provided "as is" without express or implied warranty. -- -- Copyright (c) 1994 -- Hewlett-Packard Company -- -- Permission to use, copy, modify, distribute and sell this software -- and its documentation for any purpose is hereby granted without fee, -- provided that the above copyright notice appears in all copies and -- that both that copyright notice and this permission notice appear -- in supporting documentation. 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It is provided "as is" without express or implied warranty. -- --><Head><Title>equal</Title><!-- Generated by htmldoc --></HEAD><BODY BGCOLOR="#ffffff" LINK="#0000ee" TEXT="#000000" VLINK="#551a8b" ALINK="#ff0000"> <IMG SRC="CorpID.gif" ALT="SGI" HEIGHT="43" WIDTH="151"> <!--end header--><BR Clear><H1>equal</H1><Table CellPadding=0 CellSpacing=0 width=100%><TR><TD Align=left><Img src = "algorithms.gif" Alt="" WIDTH = "194" HEIGHT = "38" ></TD><TD Align=right><Img src = "function.gif" Alt="" WIDTH = "194" HEIGHT = "38" ></TD></TR><TR><TD Align=left VAlign=top><b>Category</b>: algorithms</TD><TD Align=right VAlign=top><b>Component type</b>: function</TD></TR></Table><h3>Prototype</h3><tt>Equal</tt> is an overloaded name; there are actually two <tt>equal</tt>functions.<pre>template <class <A href="InputIterator.html">InputIterator</A>1, class <A href="InputIterator.html">InputIterator</A>2>bool equal(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2);template <class <A href="InputIterator.html">InputIterator</A>1, class <A href="InputIterator.html">InputIterator</A>2, class <A href="BinaryPredicate.html">BinaryPredicate</A>>bool equal(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, BinaryPredicate binary_pred);</pre> <h3>Description</h3><tt>Equal</tt> returns <tt>true</tt> if the two ranges <tt>[first1, last1)</tt> and<tt>[first2, first2 + (last1 - first1))</tt> are identical when comparedelement-by-element, and otherwise returns <tt>false</tt>. <A href="#1">[1]</A> <P>The first version of <tt>equal</tt> returns <tt>true</tt> if and only iffor every iterator <tt>i</tt> in <tt>[first1, last1)</tt>, <tt>*i == *(first2 + (i - first1))</tt>. The second version of <tt>equal</tt> returns <tt>true</tt> if and only iffor every iterator <tt>i</tt> in <tt>[first1, last1)</tt>, <tt>binary_pred(*i, *(first2 + (i - first1))</tt> is <tt>true</tt>. <h3>Definition</h3>Defined in the standard header <A href="algorithm">algorithm</A>, and in the nonstandardbackward-compatibility header <A href="algo.h">algo.h</A>.<h3>Requirements on types</h3>For the first version:<UL><LI><tt>InputIterator1</tt> is a model of <A href="InputIterator.html">Input Iterator</A>.<LI><tt>InputIterator2</tt> is a model of <A href="InputIterator.html">Input Iterator</A>.<LI><tt>InputIterator1</tt>'s value type is a model of <A href="EqualityComparable.html">Equality Comparable</A>.<LI><tt>InputIterator2</tt>'s value type is a model of <A href="EqualityComparable.html">Equality Comparable</A>.<LI><tt>InputIterator1</tt>'s value type can be compared for equality with <tt>InputIterator2</tt>'s value type. </UL>For the second version:<UL><LI><tt>InputIterator1</tt> is a model of <A href="InputIterator.html">Input Iterator</A>.<LI><tt>InputIterator2</tt> is a model of <A href="InputIterator.html">Input Iterator</A>.<LI><tt>BinaryPredicate</tt> is a model of <A href="BinaryPredicate.html">Binary Predicate</A>.<LI><tt>InputIterator1</tt>'s value type is convertible to <tt>BinaryPredicate</tt>'s first argument type.<LI><tt>InputIterator2</tt>'s value type is convertible to <tt>BinaryPredicate</tt>'s second argument type.</UL><h3>Preconditions</h3><UL><LI><tt>[first1, last1)</tt> is a valid range.<LI><tt>[first2, first2 + (last2 - last1))</tt> is a valid range.</UL><h3>Complexity</h3>Linear. At most <tt>last1 - first1</tt> comparisons.<h3>Example</h3><pre>int A1[] = { 3, 1, 4, 1, 5, 9, 3 };int A2[] = { 3, 1, 4, 2, 8, 5, 7 };const int N = sizeof(A1) / sizeof(int);cout << "Result of comparison: " << equal(A1, A1 + N, A2) << endl;</pre><h3>Notes</h3><P><A name="1">[1]</A>Note that this is very similar to the behavior of <tt><A href="mismatch.html">mismatch</A></tt>: Theonly real difference is that while <tt>equal</tt> will simply return <tt>false</tt>if the two ranges differ, <tt><A href="mismatch.html">mismatch</A></tt> returns the first location wherethey do differ. The expression <tt>equal(f1, l1, f2)</tt> is precisely equivalentto the expression <tt>mismatch(f1, l1, f2).first == l1</tt>, and this is infact how <tt>equal</tt> could be implemented.<h3>See also</h3><tt><A href="mismatch.html">mismatch</A></tt>, <tt><A href="search.html">search</A></tt>, <tt><A href="find.html">find</A></tt>, <tt><A href="find_if.html">find_if</A></tt><!--start footer--> <HR SIZE="6"><A href="http://www.sgi.com/"><IMG SRC="surf.gif" HEIGHT="54" WIDTH="54" ALT="[Silicon Surf]"></A><A HREF="index.html"><IMG SRC="stl_home.gif" HEIGHT="54" WIDTH="54" ALT="[STL Home]"></A><BR><FONT SIZE="-2"><A href="http://www.sgi.com/Misc/sgi_info.html" TARGET="_top">Copyright © 1999 Silicon Graphics, Inc.</A> All Rights Reserved.</FONT><FONT SIZE="-3"><a href="http://www.sgi.com/Misc/external.list.html" TARGET="_top">TrademarkInformation</A></FONT><P></BODY></HTML> ⌨️ 快捷键说明
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