std::regex_iterator<BidirIt,CharT,Traits>::regex_iterator
From cppreference.com
regex_iterator(); |
(1) | (since C++11) |
regex_iterator( BidirIt a, BidirIt b, const regex_type& re, std::regex_constants::match_flag_type m = std::regex_constants::match_default ); |
(2) | (since C++11) |
regex_iterator( const regex_iterator& ); |
(3) | (since C++11) |
regex_iterator( BidirIt, BidirIt, const regex_type&&, std::regex_constants::match_flag_type = std::regex_constants::match_default ) = delete; |
(4) | (since C++11) |
Constructs a new regex_iterator:
1) Default constructor. Constructs an end-of-sequence iterator.
2) Constructs a
regex_iterator from the sequence of characters [a, b), the regular expression re, and a flag m that governs matching behavior. This constructor performs an initial call to std::regex_search with this data. If the result of this initial call is false, *this is set to an end-of-sequence iterator.3) Copies a
regex_iterator.4) The overload (2) is not allowed to be called with a temporary regex, since the returned iterator would be immediately invalidated.
Parameters
| a | - | LegacyBidirectionalIterator to the beginning of the target character sequence |
| b | - | LegacyBidirectionalIterator to the end of the target character sequence |
| re | - | regular expression used to search the target character sequence |
| m | - | flags that govern the behavior of re
|
Example
Run this code
#include <iostream>
#include <regex>
#include <string_view>
int main()
{
constexpr std::string_view str{R"(
#ONE: *p = &Mass;
#Two: MOV %rd, 42
)"};
const std::regex re("[a-w]");
// create regex_iterator, overload (2)
auto it = std::regex_iterator<std::string_view::iterator>
{
str.cbegin(), str.cend(),
re // re is lvalue; if an immediate expression was used
// instead, e.g. std::regex{"[a-z]"}, this would
// produce an error since overload (4) is deleted
};
for (decltype(it) last /* overload (1) */; it != last; ++it)
std::cout << (*it).str();
std::cout << '\n';
}
Output:
password
Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
| DR | Applied to | Behavior as published | Correct behavior |
|---|---|---|---|
| LWG 2332 | C++11 | a regex_iterator constructed from a temporarybasic_regex became invalid immediately
|
such construction is disallowed via a deleted overload |