C++ Regex Library - regex_iterator


Description

It is an iterator type to iterate over different matches of a same regex pattern in a sequence.

Declaration

Following is the declaration for std::regex_iterator.

emplate <class BidirectionalIterator,
          class charT=typename iterator_traits<BidirectionalIterator>::value_type,
          class traits=regex_traits<charT> > class regex_iterator;

C++11

emplate <class BidirectionalIterator,
          class charT=typename iterator_traits<BidirectionalIterator>::value_type,
          class traits=regex_traits<charT> > class regex_iterator;

C++14

emplate <class BidirectionalIterator,
          class charT=typename iterator_traits<BidirectionalIterator>::value_type,
          class traits=regex_traits<charT> > class regex_iterator;

Parameters

  • BidirectionalIterator − It is a bidirectional iterator type that iterates on the target sequence of characters.

  • charT − It is a char type.

  • traits − It is a regex traits type.

Return Value

It returns a string object with the resulting sequence.

Exceptions

No-noexcept − this member function never throws exceptions.

Example

In below example for std::regex_iterator.

#include <regex>
#include <iterator>
#include <iostream>
#include <string>

int main() {
   const std::string s = "Tutorialspoint.com india pvt ltd.";
 
   std::regex words_regex("[^\\s]+");
   auto words_begin = 
      std::sregex_iterator(s.begin(), s.end(), words_regex);
   auto words_end = std::sregex_iterator();
 
   std::cout << "Found " 
      << std::distance(words_begin, words_end) 
      << " words:\n";
 
   for (std::sregex_iterator i = words_begin; i != words_end; ++i) {
      std::smatch match = *i;
      std::string match_str = match.str();
      std::cout << match_str << '\n';
   }
}

The output should be like this −

Found 4 words:
Tutorialspoint.com
india
pvt
ltd.
regex.htm
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