1<?xml version="1.0" encoding="UTF-8" standalone="no"?> 2<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 3<html xmlns="http://www.w3.org/1999/xhtml"> 4 <head> 5 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> 6 <title>operator-</title> 7 <link rel="stylesheet" href="apiReference.css" type="text/css" /> 8 <meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /> 9 <link rel="start" href="index.html" title="Berkeley DB C++ Standard Template Library API Reference" /> 10 <link rel="up" href="db_vector_base_iterator.html" title="Chapter��12.�� Db_vector_base_iterator" /> 11 <link rel="prev" href="stldb_vector_base_iteratoroperator_ia.html" title="operator+=" /> 12 <link rel="next" href="stldb_vector_base_iteratoroperator_sa.html" title="operator-=" /> 13 </head> 14 <body> 15 <div class="navheader"> 16 <table width="100%" summary="Navigation header"> 17 <tr> 18 <th colspan="3" align="center"> 19operator- 20</th> 21 </tr> 22 <tr> 23 <td width="20%" align="left"><a accesskey="p" href="stldb_vector_base_iteratoroperator_ia.html">Prev</a>��</td> 24 <th width="60%" align="center">Chapter��12.�� 25 Db_vector_base_iterator </th> 26 <td width="20%" align="right">��<a accesskey="n" href="stldb_vector_base_iteratoroperator_sa.html">Next</a></td> 27 </tr> 28 </table> 29 <hr /> 30 </div> 31 <div class="sect1" lang="en" xml:lang="en"> 32 <div class="titlepage"> 33 <div> 34 <div> 35 <h2 class="title" style="clear: both"><a id="stldb_vector_base_iteratoroperator_sub"></a> 36operator- 37</h2> 38 </div> 39 </div> 40 </div> 41 <div class="sect2" lang="en" xml:lang="en"> 42 <div class="titlepage"> 43 <div> 44 <div> 45 <h3 class="title"><a id="func_details"></a> 46Function Details</h3> 47 </div> 48 </div> 49 </div> 50 <pre class="programlisting"> 51self��operator-(difference_type��n)��const 52 </pre> 53 <div class="sect3" lang="en" xml:lang="en"> 54 <div class="titlepage"></div> 55 <p>Iterator movement operator. </p> 56 <p>Return another iterator by moving this iterator backward by n elements. </p> 57 </div> 58 <div class="sect3" lang="en" xml:lang="en"> 59 <div class="titlepage"> 60 <div> 61 <div> 62 <h4 class="title"><a id="id1560204"></a> 63Parameters</h4> 64 </div> 65 </div> 66 </div> 67 <div class="sect4" lang="en" xml:lang="en"> 68 <div class="titlepage"> 69 <div> 70 <div> 71 <h5 class="title"><a id="id1560322"></a> 72 n </h5> 73 </div> 74 </div> 75 </div> 76 <p>The amount and direction of movement. If negative, will move backward by |n| element. </p> 77 </div> 78 </div> 79 <div class="sect3" lang="en" xml:lang="en"> 80 <div class="titlepage"> 81 <div> 82 <div> 83 <h4 class="title"><a id="id1560198"></a> 84Return Value</h4> 85 </div> 86 </div> 87 </div> 88 <p>The new iterator at new position. </p> 89 </div> 90 <pre class="programlisting"> 91difference_type��operator-(const��self��&itr)��const 92 </pre> 93 <div class="sect3" lang="en" xml:lang="en"> 94 <div class="titlepage"></div> 95 <p>Iterator distance operator. </p> 96 <p>Return the index difference of this iterator and itr, so if this iterator sits on an element with a smaller index, this call will return a negative number. </p> 97 </div> 98 <div class="sect3" lang="en" xml:lang="en"> 99 <div class="titlepage"> 100 <div> 101 <div> 102 <h4 class="title"><a id="id1560417"></a> 103Parameters</h4> 104 </div> 105 </div> 106 </div> 107 <div class="sect4" lang="en" xml:lang="en"> 108 <div class="titlepage"> 109 <div> 110 <div> 111 <h5 class="title"><a id="id1560377"></a> 112 itr </h5> 113 </div> 114 </div> 115 </div> 116 <p>The other iterator to substract. itr can be the invalid iterator after last element or before first element, their index will be regarded as last element's index + 1 and -1 respectively. </p> 117 </div> 118 </div> 119 <div class="sect3" lang="en" xml:lang="en"> 120 <div class="titlepage"> 121 <div> 122 <div> 123 <h4 class="title"><a id="id1560323"></a> 124Return Value</h4> 125 </div> 126 </div> 127 </div> 128 <p>The index difference. </p> 129 </div> 130 </div> 131 <div class="sect2" lang="en" xml:lang="en"> 132 <div class="titlepage"> 133 <div> 134 <div> 135 <h3 class="title"><a id="id1560341"></a> 136Group: Iterator movement operators.</h3> 137 </div> 138 </div> 139 </div> 140 <p>When we talk about iterator movement, we think the container is a uni-directional range, represented by [begin, end), and this is true no matter we are using iterators or reverse iterators.</p> 141 <p>When an iterator is moved closer to "begin", we say it is moved forward, otherwise we say it is moved backward. </p> 142 </div> 143 <div class="sect2" lang="en" xml:lang="en"> 144 <div class="titlepage"> 145 <div> 146 <div> 147 <h3 class="title"><a id="id1560371"></a> 148Class</h3> 149 </div> 150 </div> 151 </div> 152 <p> 153 <a class="link" href="db_vector_base_iterator.html" title="Chapter��12.�� Db_vector_base_iterator"> 154 db_vector_base_iterator</a> 155 </p> 156 </div> 157 </div> 158 <div class="navfooter"> 159 <hr /> 160 <table width="100%" summary="Navigation footer"> 161 <tr> 162 <td width="40%" align="left"><a accesskey="p" href="stldb_vector_base_iteratoroperator_ia.html">Prev</a>��</td> 163 <td width="20%" align="center"> 164 <a accesskey="u" href="db_vector_base_iterator.html">Up</a> 165 </td> 166 <td width="40%" align="right">��<a accesskey="n" href="stldb_vector_base_iteratoroperator_sa.html">Next</a></td> 167 </tr> 168 <tr> 169 <td width="40%" align="left" valign="top"> 170operator+= 171��</td> 172 <td width="20%" align="center"> 173 <a accesskey="h" href="index.html">Home</a> 174 </td> 175 <td width="40%" align="right" valign="top">�� 176operator-= 177</td> 178 </tr> 179 </table> 180 </div> 181 </body> 182</html> 183