//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 hrefex(R"##(href\s*=\s*"([^"]*)")##",
		std::regex_constants::icase | std::regex_constants::optimize);
	
	string s;
	while(!getline(cin,s).eof()) {
		// iterators include cregex_iterator (references const char*)
		//                  wcregex_iterator (references const wchar_t *)
		//                   sregex_iterator (ref string::const_iterator)
		//                  wsregex_iterator (ref wstring::const_iterator)
		//    can make your own (regex_iterator<BiDirIterator,CharT>)
		/*
		sregex_iterator b(s.cbegin(),s.cend(),hrefex);
		sregex_iterator e;
		
		for(auto i=b;i!=e;++i)
			cout << i->str() << endl;

		// OR
		
		for(sregex_iterator b(begin(s),end(s),hrefex),e;b!=e;++b)
			cout << b->str() << endl;

		*/
		// OR
		
		
		// or could use for_each:
		/*
		for_each(sregex_iterator(begin(s),end(s),hrefex),
			    sregex_iterator(),
		         [](const std::smatch &m){ cout << m.str() << endl;}
		        );
		*/

		// iterator is dereferences to get match_results
		// which has methods including
		//   str(): returns string (see above)
		//   size(): returns number of sub matches
		//   operator[int i]: returns object type sub_match
		//   				for the ith sub-match
		//   	note: [0] is the whole thing. [1] is the first sub-exp
		//
		// a sub_match has methods including
		//   str(): returns the submatch string
		//   length(): length of the submatch string (0 if no match)
		//   matched(): bool of whether submatch is part of reg-ex match


		// so, to print out the URLs (without the href) we could do:
		for(sregex_iterator b(begin(s),end(s),hrefex),e;b!=e;++b)
			cout << (*b)[1].str() << endl;
	}
}