OutputIt remove_copy( InputIt first, InputIt last,
class T = typename std::iterator_traits
<InputIt>::value_type >
constexpr OutputIt remove_copy( InputIt first, InputIt last,
class ForwardIt1, class ForwardIt2, class T >
ForwardIt2 remove_copy( ExecutionPolicy&& policy,
ForwardIt1 first, ForwardIt1 last,
class ForwardIt1, class ForwardIt2,
class T = typename std::iterator_traits
<ForwardIt1>::value_type >
ForwardIt2 remove_copy( ExecutionPolicy&& policy,
ForwardIt1 first, ForwardIt1 last,
OutputIt remove_copy_if( InputIt first, InputIt last,
class ForwardIt1, class ForwardIt2, class UnaryPred >
ForwardIt2 remove_copy_if( ExecutionPolicy&& policy,
ForwardIt1 first, ForwardIt1 last,
Copies elements from the range [
first,
last)
, to another range beginning at d_first, omitting the elements which satisfy specific criteria.
1) Ignores all elements that are equal to value (using operator==).
3) Ignores all elements for which predicate p returns true.
2,4) Same as (1,3), but executed according to policy.
These overloads participate in overload resolution only if all following conditions are satisfied:
If *d_first = *first is invalid(until C++20)*first is not writable to d_first(since C++20), the program is ill-formed.
If source and destination ranges overlap, the behavior is undefined.
[edit] Parameters first, last - the pair of iterators defining the source range of elements to copy d_first - the beginning of the destination range value - the value of the elements not to copy policy - the execution policy to use Type requirements -InputIt
must meet the requirements of LegacyInputIterator. -OutputIt
must meet the requirements of LegacyOutputIterator. -ForwardIt1, ForwardIt2
must meet the requirements of LegacyForwardIterator. -UnaryPred
must meet the requirements of Predicate. [edit] Return value
Iterator to the element past the last element copied.
[edit] ComplexityGiven \(\scriptsize N\)N as std::distance(first, last):
1,2) Exactly \(\scriptsize N\)N comparisons with value using operator==.
3,4) Exactly \(\scriptsize N\)N applications of the predicate p.
For the overloads with an ExecutionPolicy, there may be a performance cost if ForwardIt1
's value_type
is not MoveConstructible.
The overloads with a template parameter named ExecutionPolicy
report errors as follows:
ExecutionPolicy
is one of the standard policies, std::terminate is called. For any other ExecutionPolicy
, the behavior is implementation-defined.template<class InputIt, class OutputIt, class T = typename std::iterator_traits<InputIt>::value_type> constexpr OutputIt remove_copy(InputIt first, InputIt last, OutputIt d_first, const T& value) { for (; first != last; ++first) if (!(*first == value)) *d_first++ = *first; return d_first; }remove_copy_if (3)
template<class InputIt, class OutputIt, class UnaryPred> constexpr OutputIt remove_copy_if(InputIt first, InputIt last, OutputIt d_first, UnaryPred p) { for (; first != last; ++first) if (!p(*first)) *d_first++ = *first; return d_first; }[edit] Notes [edit] Example
#include <algorithm> #include <complex> #include <iomanip> #include <iostream> #include <iterator> #include <string> #include <vector> int main() { // Erase the hash characters '#' on the fly. std::string str = "#Return #Value #Optimization"; std::cout << "before: " << std::quoted(str) << '\n'; std::cout << "after: \""; std::remove_copy(str.begin(), str.end(), std::ostream_iterator<char>(std::cout), '#'); std::cout << "\"\n"; // Erase {1, 3} value on the fly. std::vector<std::complex<double>> nums{{2, 2}, {1, 3}, {4, 8}, {1, 3}}; std::remove_copy(nums.begin(), nums.end(), std::ostream_iterator<std::complex<double>>(std::cout), #ifdef __cpp_lib_algorithm_default_value_type {1, 3}); // T gets deduced #else std::complex<double>{1, 3}); #endif }
Output:
before: "#Return #Value #Optimization" after: "Return Value Optimization" (2,2)(4,8)[edit] 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 779 C++98T
was required to be EqualityComparable, but
ForwardIt
is not always T
required *d_first = *first
RetroSearch is an open source project built by @garambo | Open a GitHub Issue
Search and Browse the WWW like it's 1997 | Search results from DuckDuckGo
HTML:
3.2
| Encoding:
UTF-8
| Version:
0.7.4