page86.html
来自「wqeqwvrw rkjqhwrjwq jkhrjqwhrwq jkhrwq」· HTML 代码 · 共 43 行
HTML
43 行
<HTML>
<HEAD>
<TITLE>Array Subscripting Operator</TITLE>
</HEAD>
<BODY bgcolor="#FFFFFF">
<img src="cover75.gif" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/icons/cover75.gif" alt="Logo" align=right>
<b>Data Structures and Algorithms
with Object-Oriented Design Patterns in C++</b><br>
<A NAME="tex2html2965" HREF="page87.html" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/html/page87.html"><IMG WIDTH=37 HEIGHT=24 ALIGN=BOTTOM ALT="next" SRC="next_motif.gif" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/icons/next_motif.gif"></A> <A NAME="tex2html2963" HREF="page80.html" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/html/page80.html"><IMG WIDTH=26 HEIGHT=24 ALIGN=BOTTOM ALT="up" SRC="up_motif.gif" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/icons/up_motif.gif"></A> <A NAME="tex2html2957" HREF="page85.html" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/html/page85.html"><IMG WIDTH=63 HEIGHT=24 ALIGN=BOTTOM ALT="previous" SRC="previous_motif.gif" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/icons/previous_motif.gif"></A> <A NAME="tex2html2967" HREF="page9.html" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/html/page9.html"><IMG WIDTH=65 HEIGHT=24 ALIGN=BOTTOM ALT="contents" SRC="contents_motif.gif" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/icons/contents_motif.gif"></A> <A NAME="tex2html2968" HREF="page620.html" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/html/page620.html"><IMG WIDTH=43 HEIGHT=24 ALIGN=BOTTOM ALT="index" SRC="index_motif.gif" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/icons/index_motif.gif"></A> <BR><HR>
<H2><A NAME="SECTION005160000000000000000">Array Subscripting Operator</A></H2>
<P>
Program <A HREF="page86.html#progarray6c" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/html/page86.html#progarray6c"><IMG ALIGN=BOTTOM ALT="gif" SRC="cross_ref_motif.gif" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/icons/cross_ref_motif.gif"></A> defines two functions,
each of which overloads the array subscripting operation.
The purpose of overloading <tt>operator[]</tt>
is to allow arbitrary subscript ranges and to provide array bounds-checking.
The array subscripting operator,
<tt>operator[]</tt> is provided in two forms.
One which operates on a <tt>const</tt> array object
and returns a <tt>const</tt> reference to an object of type <tt>T</tt>;
and another which does the same for non-<tt>const</tt> objects.
The code in both instances is identical.
The <tt>position</tt> argument is checked and then
a reference to the selected item is returned.
In the event of an array-bounds error,
an <tt>outofrange</tt><A NAME=2789> </A><A NAME="tex2html128" HREF="footnode.html#2880" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/html/footnode.html#2880"><IMG ALIGN=BOTTOM ALT="gif" SRC="foot_motif.gif" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/icons/foot_motif.gif"></A>
<em>exception</em><A NAME=2792> </A> is thrown.
<P>
We will assume that in a bug-free program there will never
be an array-bounds error.
Therefore, the running time of <tt>operator[]</tt> is a constant.
I.e., <I>T</I>(<I>n</I>)=<I>O</I>(1).
This is, after all, the sole reason for using an array--the time it takes to access the <IMG WIDTH=17 HEIGHT=13 ALIGN=BOTTOM ALT="tex2html_wrap_inline58387" SRC="img77.gif" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/html/img77.gif" > element of the array is a constant!
<P>
<P><A NAME="2882"> </A><A NAME="progarray6c"> </A> <IMG WIDTH=575 HEIGHT=333 ALIGN=BOTTOM ALT="program2795" SRC="img606.gif" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/html/img606.gif" ><BR>
<STRONG>Program:</STRONG> <tt>Array<T></tt> Class Subscripting Function Definitions<BR>
<P><HR><A NAME="tex2html2965" HREF="page87.html" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/html/page87.html"><IMG WIDTH=37 HEIGHT=24 ALIGN=BOTTOM ALT="next" SRC="next_motif.gif" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/icons/next_motif.gif"></A> <A NAME="tex2html2963" HREF="page80.html" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/html/page80.html"><IMG WIDTH=26 HEIGHT=24 ALIGN=BOTTOM ALT="up" SRC="up_motif.gif" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/icons/up_motif.gif"></A> <A NAME="tex2html2957" HREF="page85.html" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/html/page85.html"><IMG WIDTH=63 HEIGHT=24 ALIGN=BOTTOM ALT="previous" SRC="previous_motif.gif" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/icons/previous_motif.gif"></A> <A NAME="tex2html2967" HREF="page9.html" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/html/page9.html"><IMG WIDTH=65 HEIGHT=24 ALIGN=BOTTOM ALT="contents" SRC="contents_motif.gif" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/icons/contents_motif.gif"></A> <A NAME="tex2html2968" HREF="page620.html" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/html/page620.html"><IMG WIDTH=43 HEIGHT=24 ALIGN=BOTTOM ALT="index" SRC="index_motif.gif" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/icons/index_motif.gif"></A> <P><ADDRESS>
<img src="bruno.gif" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/icons/bruno.gif" alt="Bruno" align=right>
<a href="javascript:if(confirm('http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/copyright.html \n\nThis file was not retrieved by Teleport Pro, because it is addressed on a domain or path outside the boundaries set for its Starting Address. \n\nDo you want to open it from the server?'))window.location='http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/copyright.html'" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/copyright.html">Copyright © 1997</a> by <a href="javascript:if(confirm('http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/signature.html \n\nThis file was not retrieved by Teleport Pro, because it is addressed on a domain or path outside the boundaries set for its Starting Address. \n\nDo you want to open it from the server?'))window.location='http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/signature.html'" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/signature.html">Bruno R. Preiss, P.Eng.</a> All rights reserved.
</ADDRESS>
</BODY>
</HTML>
⌨️ 快捷键说明
复制代码Ctrl + C
搜索代码Ctrl + F
全屏模式F11
增大字号Ctrl + =
减小字号Ctrl + -
显示快捷键?