Regular Expression 正则表达式-3 (C++)

王朝c/c++·作者佚名  2006-01-09
窄屏简体版  字體: |||超大  

最后用C++实现了一把,因为STL中尚未包含Regular Expression,因此我使用了Boost中的Regex++。不过因为不是很熟悉,所以代码很蹩脚,将就看了。呵呵。

#include <string>

#include <boost/regex.hpp>

#include <iostream>

#include <fstream>

using namespace std;

void readFile( const char* filename, string& str );

void writeFile( const char* filename, const string str );

void filter( const string input, string& output );

int main(int argc, const char* argv[])

{

if( argc < 3 )

{

cout<< "Please enter 2 filenames(e.g. In.txt Out.txt)" << endl;

return 1;

}

string strIn, strOut;

readFile( argv[1], strIn );

filter( strIn, strOut );

writeFile( argv[2], strOut );

}

void readFile( const char* filename, string& str )

{

ifstream in( filename );

str.erase();

str.reserve( in.rdbuf()->in_avail() );

string strTemp;

while( !in.eof() )

{

in >> strTemp;

str.append(strTemp);

}

in.close();

}

void writeFile( const char* filename, const string str )

{

ofstream out( filename );

out.write( str.c_str(), (streamsize)str.length() );

out.flush();

out.close();

}

void filter( const string input, string& output )

{

output.erase();

output.reserve( input.length() );

boost::regex expression("\"(\\w+):(\\w+)%(\\w+)\"");

boost::smatch group;

boost::regex_constants::match_flag_type flags = boost::regex_constants::match_default;

string::const_iterator start, end;

start = input.begin();

end = input.end();

while( boost::regex_search( start, end, group, expression, flags ))

{

output.append( group[1] );

output.append( ":" );

output.append( group[2] );

output.append( "*" );

output.append( group[3] );

output.append( "," );

output.append( "\n" );

// update

start = group[0].second;

flags |= boost::regex_constants::match_prev_avail;

flags |= boost::regex_constants::match_not_bob;

}

return;

}

 
 
 
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