regex/example/snippets/partial_regex_match.cpp

70 lines
1.7 KiB
C++

/*
*
* Copyright (c) 1998-2002
* John Maddock
*
* Use, modification and distribution are subject to the
* Boost Software License, Version 1.0. (See accompanying file
* LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
*
*/
/*
* LOCATION: see http://www.boost.org for most recent version.
* FILE partial_regex_match.cpp
* VERSION see <boost/version.hpp>
* DESCRIPTION: regex_match example using partial matches.
*/
#include <boost/regex.hpp>
#include <string>
#include <iostream>
boost::regex e("(\\d{3,4})[- ]?(\\d{4})[- ]?(\\d{4})[- ]?(\\d{4})");
bool is_possible_card_number(const std::string& input)
{
//
// return false for partial match, true for full match, or throw for
// impossible match based on what we have so far...
boost::match_results<std::string::const_iterator> what;
if(0 == boost::regex_match(input, what, e, boost::match_default | boost::match_partial))
{
// the input so far could not possibly be valid so reject it:
throw std::runtime_error("Invalid data entered - this could not possibly be a valid card number");
}
// OK so far so good, but have we finished?
if(what[0].matched)
{
// excellent, we have a result:
return true;
}
// what we have so far is only a partial match...
return false;
}
int main(int argc, char* argv[])
{
try{
std::string input;
if(argc > 1)
input = argv[1];
else
std::cin >> input;
if(is_possible_card_number(input))
{
std::cout << "Matched OK..." << std::endl;
}
else
std::cout << "Got a partial match..." << std::endl;
}
catch(const std::exception& e)
{
std::cout << e.what() << std::endl;
}
return 0;
}