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bf93977326
Applied these changes. The revision date should be changed from ''25 December, 2006'' to ''9 June 2010''. You could also change the webbot element from ''s-format="%d %B, %Y"'' to ''s-format="%d %B %Y"''. The comma is superfluous in that format. [SVN r62752]
121 lines
3.9 KiB
HTML
121 lines
3.9 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<html>
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<head>
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<meta http-equiv="Content-Language" content="en-us">
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<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
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<meta name="GENERATOR" content="Microsoft FrontPage 6.0">
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<meta name="ProgId" content="FrontPage.Editor.Document">
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<title>Introduction</title>
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</head>
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<body bgcolor="#FFFFFF">
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<p><img src="../../boost.png" alt="C++ Boost" width="277" height=
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"86"/><br></p>
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<h1 align="center">Introduction</h1>
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<p align="left">The Boost Tokenizer package provides a flexible and
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easy-to-use way to break a string or other character sequence into a series
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of tokens. Below is a simple example that will break up a phrase into
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words.</p>
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<div align="left">
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<pre>
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// simple_example_1.cpp
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#include<iostream>
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#include<boost/tokenizer.hpp>
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#include<string>
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int main(){
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using namespace std;
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using namespace boost;
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string s = "This is, a test";
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tokenizer<> tok(s);
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for(tokenizer<>::iterator beg=tok.begin(); beg!=tok.end();++beg){
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cout << *beg << "\n";
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}
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}
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</pre>
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</div>
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<p align="left">You can choose how the string gets parsed by using the
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TokenizerFunction. If you do not specify anything, the default
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TokenizerFunction is <em>char_delimiters_separator<char></em> which
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defaults to breaking up a string based on space and punctuation. Here is an
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example using another TokenizerFunction called
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<em>escaped_list_separator</em>. This TokenizerFunction parses a superset
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of comma-separated value (CSV) lines. The format looks like this:</p>
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<p align="left">Field 1,"putting quotes around fields, allows commas",Field
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3</p>
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<p align="left">Below is an example that will break the previous line into
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its three fields.</p>
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<div align="left">
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<pre>
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// simple_example_2.cpp
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#include<iostream>
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#include<boost/tokenizer.hpp>
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#include<string>
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int main(){
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using namespace std;
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using namespace boost;
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string s = "Field 1,\"putting quotes around fields, allows commas\",Field 3";
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tokenizer<escaped_list_separator<char> > tok(s);
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for(tokenizer<escaped_list_separator<char> >::iterator beg=tok.begin(); beg!=tok.end();++beg){
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cout << *beg << "\n";
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}
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}
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</pre>
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</div>
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<p align="left">Finally, for some TokenizerFunctions you have to pass
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something into the constructor in order to do anything interesting. An
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example is the offset_separator. This class breaks a string into tokens based
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on offsets. For example, when <em>12252001</em> is parsed using offsets of
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2,2,4 it becomes <em>12 25 2001</em>. Below is the code used.</p>
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<div align="left">
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<pre>
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// simple_example_3.cpp
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#include<iostream>
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#include<boost/tokenizer.hpp>
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#include<string>
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int main(){
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using namespace std;
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using namespace boost;
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string s = "12252001";
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int offsets[] = {2,2,4};
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offset_separator f(offsets, offsets+3);
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tokenizer<offset_separator> tok(s,f);
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for(tokenizer<offset_separator>::iterator beg=tok.begin(); beg!=tok.end();++beg){
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cout << *beg << "\n";
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}
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}
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</pre>
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</div>
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<p align="left"> </p>
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<hr>
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<p><a href="http://validator.w3.org/check?uri=referer"><img border="0" src=
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"../../doc/images/valid-html401.png" alt="Valid HTML 4.01 Transitional"
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height="31" width="88"></a></p>
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<p>Revised
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<!--webbot bot="Timestamp" s-type="EDITED" s-format="%d %B %Y" startspan -->9 June 2010<!--webbot bot="Timestamp" endspan i-checksum="38518" --></p>
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<p><i>Copyright © 2001 John R. Bandela</i></p>
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<p><i>Distributed under the Boost Software License, Version 1.0. (See
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accompanying file <a href="../../LICENSE_1_0.txt">LICENSE_1_0.txt</a> or
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copy at <a href=
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"http://www.boost.org/LICENSE_1_0.txt">http://www.boost.org/LICENSE_1_0.txt</a>)</i></p>
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</body>
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</html>
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