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#include <string>
#include <iostream>
#include <boost/regex.hpp>
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;
}
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