//clang
#include <regex>
#include <iostream>

using namespace std;

int main(int argc, char **argv) {
	// note!  HTML is *NOT* parsable with regular expressions
	// this is just an example if you wanted to try
	//
	// regex is just basic_regex<char>
	regex quotedword(R"##("\w+")##");
	// default reg-ex lang is ECMA-262 -- essentially Perl 5
	
	// can also construct with additional arg of reg-ex lang
	regex qword2(R"##("[[:alpha:]]\+)")##",std::regex_constants::egrep);
		// options are basic, extended, awk, grep, egrep, ECMAScript
		
		// can combine with matching options:
		//   icase = case insenstive
		//   nosubs = do not store sub-exp matchs
		//   optimize = make construction slower to make match faster
		//   collate = character ranges are locale sensitive
	
	string s;
	while(!getline(cin,s).eof()) {
		if (regex_match(s,quotedword))
			cout << "whole string matches" << endl;
		if (regex_search(s,quotedword))
			cout << "substring matches" << endl;
		string news = regex_replace(s,quotedword,R"("xxxxx")");
		cout << news << endl;
	}
}