std::match_results::prefix

 

C++

Language

Concepts

Utilities library

Strings library

Containers library

Algorithms library

Iterators library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

 

Regular expressions library

Classes

basic_regex (C++11)

sub_match (C++11)

match_results (C++11)

Algorithms

regex_match (C++11)

regex_search (C++11)

regex_replace (C++11)

Iterators

regex_iterator (C++11)

regex_token_iterator (C++11)

Exceptions

regex_error (C++11)

Traits

regex_traits (C++11)

Constants

syntax_option_type (C++11)

match_flag_type (C++11)

error_type (C++11)

 

std::match_results

Member functions

match_results::match_results (C++11)

match_results::~match_results (C++11)

match_results::operator= (C++11)

match_results::get_allocator (C++11)

State

match_results::ready (C++11)

Element access

match_results::size (C++11)

match_results::max_size (C++11)

match_results::empty (C++11)

match_results::length (C++11)

match_results::position (C++11)

match_results::str (C++11)

match_results::operator_at (C++11)

match_results::prefix (C++11)

match_results::suffix (C++11)

Iterators

match_results::begin match_results::cbegin (C++11)

match_results::end match_results::cend (C++11)

Format

match_results::format (C++11)

Modifiers

match_results::swap (C++11)

 

const_reference prefix() const;		(since C++11)

Parameters

(none)

Return value

Returns a sub_match representing the part of the target sequence between the beginning of the target sequence and the entire match of the regular expression.

Example

#include <iostream>
#include <regex>
#include <string>
 
int main()
{
  std::regex re("a(a)*b");
  std::string target("baaaby");
  std::smatch sm;
 
  std::regex_search(target, sm, re);
  std::cout << sm.prefix().str() << '\n';
}

Output:

b