1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273
|
<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>Back Insertion Sequence</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>Back Insertion Sequence</H1>
<Table CellPadding=0 CellSpacing=0 width=100%>
<TR>
<TD Align=left><Img src = "containers.gif" Alt="" WIDTH = "194" HEIGHT = "38" ></TD>
<TD Align=right><Img src = "concept.gif" Alt="" WIDTH = "194" HEIGHT = "38" ></TD>
</TR>
<TR>
<TD Align=left VAlign=top><b>Category</b>: containers</TD>
<TD Align=right VAlign=top><b>Component type</b>: concept</TD>
</TR>
</Table>
<h3>Description</h3>
A Back Insertion Sequence is a <A href="Sequence.html">Sequence</A> where it is possible
to append an element to the end, or to access the last element,
in amortized constant time. Back Insertion Sequences have special
member functions as a shorthand for those operations.
<h3>Refinement of</h3>
<A href="Sequence.html">Sequence</A>
<h3>Associated types</h3>
None, except for those of <A href="Sequence.html">Sequence</A>.
<h3>Notation</h3>
<Table>
<TR>
<TD VAlign=top>
<tt>X</tt>
</TD>
<TD VAlign=top>
A type that is a model of Back Insertion Sequence
</TD>
</TR>
<TR>
<TD VAlign=top>
<tt>a</tt>
</TD>
<TD VAlign=top>
Object of type <tt>X</tt>
</TD>
</TR>
<TR>
<TD VAlign=top>
<tt>T</tt>
</TD>
<TD VAlign=top>
The value type of <tt>X</tt>
</TD>
</TR>
<TR>
<TD VAlign=top>
<tt>t</tt>
</TD>
<TD VAlign=top>
Object of type <tt>T</tt>
</TD>
</tr>
</table>
<h3>Definitions</h3>
<h3>Valid expressions</h3>
In addition to the expressions defined in <A href="Sequence.html">Sequence</A>, the following
expressions must be valid.
<Table border>
<TR>
<TH>
Name
</TH>
<TH>
Expression
</TH>
<TH>
Type requirements
</TH>
<TH>
Return type
</TH>
</TR>
<TR>
<TD VAlign=top>
Back
</TD>
<TD VAlign=top>
<tt>a.back()</tt>
</TD>
<TD VAlign=top>
</TD>
<TD VAlign=top>
<tt>reference</tt> if <tt>a</tt> is mutable, otherwise <tt>const_reference</tt>.
</TD>
</TR>
<TR>
<TD VAlign=top>
Push back
</TD>
<TD VAlign=top>
<tt>a.push_back(t)</tt>
</TD>
<TD VAlign=top>
<tt>a</tt> is mutable.
</TD>
<TD VAlign=top>
<tt>void</tt>
</TD>
</TR>
<TR>
<TD VAlign=top>
Pop back
</TD>
<TD VAlign=top>
<tt>a.pop_back()</tt>
</TD>
<TD VAlign=top>
<tt>a</tt> is mutable.
</TD>
<TD VAlign=top>
<tt>void</tt>
</TD>
</tr>
</table>
<h3>Expression semantics</h3>
<Table border>
<TR>
<TH>
Name
</TH>
<TH>
Expression
</TH>
<TH>
Precondition
</TH>
<TH>
Semantics
</TH>
<TH>
Postcondition
</TH>
</TR>
<TR>
<TD VAlign=top>
Back
</TD>
<TD VAlign=top>
<tt>a.back()</tt>
</TD>
<TD VAlign=top>
<tt>!a.empty()</tt>
</TD>
<TD VAlign=top>
Equivalent to <tt>*(--a.end())</tt>.
</TD>
<TD VAlign=top>
</TD>
</TR>
<TR>
<TD VAlign=top>
Push back
</TD>
<TD VAlign=top>
<tt>a.push_back(t)</tt>
</TD>
<TD VAlign=top>
</TD>
<TD VAlign=top>
Equivalent to <tt>a.insert(a.end(), t)</tt>
</TD>
<TD VAlign=top>
<tt>a.size</tt> is incremented by 1. <tt>a.back()</tt> is a copy of <tt>t</tt>.
</TD>
</TR>
<TR>
<TD VAlign=top>
Pop back
</TD>
<TD VAlign=top>
<tt>a.pop_back()</tt>
</TD>
<TD VAlign=top>
<tt>!a.empty()</tt>
</TD>
<TD VAlign=top>
Equivalent to <tt>a.erase(--a.end())</tt>
</TD>
<TD VAlign=top>
<tt>a.size()</tt> is decremented by 1.
</TD>
</tr>
</table>
<h3>Complexity guarantees</h3>
Back, push back, and pop back are amortized constant time. <A href="#1">[1]</A>
<h3>Invariants</h3>
<Table border>
<TR>
<TD VAlign=top>
Symmetry of push and pop
</TD>
<TD VAlign=top>
<tt>push_back()</tt> followed by <tt>pop_back()</tt> is a null operation.
</TD>
</tr>
</table>
<h3>Models</h3>
<UL>
<LI>
<A href="Vector.html">vector</A>
<LI>
<A href="List.html">list</A>
<LI>
<A href="Deque.html">deque</A>
</UL>
<h3>Notes</h3>
<P><A name="1">[1]</A>
This complexity guarantee is the only reason that <tt>back()</tt>,
<tt>push_back()</tt>, and <tt>pop_back()</tt> are defined: they provide
no additional functionality. Not every sequence must define these
operations, but it is guaranteed that they are efficient if they
exist at all.
<h3>See also</h3>
<A href="Container.html">Container</A>, <A href="Sequence.html">Sequence</A>, <A href="FrontInsertionSequence.html">Front Insertion Sequence</A>,
<tt><A href="Vector.html">vector</A></tt>, <tt><A href="Deque.html">deque</A></tt>, <tt><A href="List.html">list</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>
|