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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. Hewlett-Packard Company makes no -- representations about the suitability of this software for any -- purpose. It is provided "as is" without express or implied warranty. -- --><Head><Title>copy_n</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>copy_n</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><pre>template <class <A href="InputIterator.html">InputIterator</A>, class Size, class <A href="OutputIterator.html">OutputIterator</A>>OutputIterator copy_n(InputIterator first, Size count, OutputIterator result);</pre> <h3>Description</h3><tt>Copy_n</tt> copies elements from the range <tt>[first, first + n)</tt> to therange <tt>[result, result + n)</tt>. That is, it performs the assignments<tt>*result = *first</tt>, <tt>*(result + 1) = *(first + 1)</tt>, and so on.Generally, for every integer <tt>i</tt> from <tt>0</tt> up to (but not including)<tt>n</tt>, <tt>copy_n</tt> performs the assignment <tt>*(result + i) = *(first + i)</tt>.Assignments are performed in forward order, <i>i.e.</i> in order ofincreasing <tt>n</tt>. <A href="#1">[1]</A><P>The return value is <tt>result + n</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>. This function is an SGIextension; it is not part of the C++ standard.<h3>Requirements on types</h3><UL><LI>InputIterator is a model of <A href="InputIterator.html">Input Iterator</A>.<LI>OutputIterator is a model of <A href="OutputIterator.html">Output Iterator</A>.<LI><tt>Size</tt> is an integral type.<LI>InputIterator's value type is convertible to a type in OutputIterator's set of value types.</UL><h3>Preconditions</h3><UL><LI><tt>n >= 0</tt>.<LI><tt>[first, first + n)</tt> is a valid range.<LI><tt>result</tt> is not an iterator within the range <tt>[first, first + n)</tt>.<LI><tt>[result, result + n)</tt> is a valid range.</UL><h3>Complexity</h3>Linear. Exactly <tt>n</tt> assignments are performed.<h3>Example</h3><pre><A href="Vector.html">vector</A><int> V(5);<A href="iota.html">iota</A>(V.begin(), V.end(), 1);<A href="List.html">list</A><int> L(V.size());copy_n(V.begin(), V.size(), L.begin());assert(<A href="equal.html">equal</A>(V.begin(), V.end(), L.begin()));</pre><h3>Notes</h3><P><A name="1">[1]</A><tt>Copy_n</tt> is almost, but not quite, redundant. If <tt>first</tt> is an <A href="InputIterator.html">input iterator</A>, as opposed to a <A href="ForwardIterator.html">forward iterator</A>, then the <tt>copy_n</tt> operation can't be expressed in terms of <tt><A href="copy.html">copy</A></tt>.<h3>See also</h3><tt><A href="copy.html">copy</A></tt>, <tt><A href="copy_backward.html">copy_backward</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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