std::partition_copy
From Cppreference
| Defined in header <algorithm>
|
||
| template< class InputIterator, class OutputIterator1,
class OutputIterator2, class UnaryPredicate > |
(C++11 feature) | |
Copies the elements that satisfy the predicate p from the range [first, last) to the range beginning at d_first_true, and copies the elements that do not satisfy p to the range beginning at d_first_false.
Contents |
[edit] Parameters
| first, last | - | the range of elements to sort | |||||||||
| d_first_true | - | the beginning of the output range for the elements that satisfy p | |||||||||
| d_first_false | - | the beginning of the output range for the elements that do not satisfy p | |||||||||
| p | - | unary predicate which returns true if the element should be placed in d_first_true. The signature of the predicate function should be equivalent to the following:
The signature does not need to have const &, but the function must not modify the objects passed to it. |
|||||||||
[edit] Return value
A pair constructed from the iterator to the end of the d_first_true range and the iterator to the end of the d_first_false range.
[edit] Complexity
Exactly distance(first, last) applications of p.
[edit] Equivalent function
template <class InputIterator, class OutputIterator1, class OutputIterator2, class UnaryPredicate> std::pair<OutputIterator1, OutputIterator2> partition_copy(InputIterator first, InputIterator last, OutputIterator1 d_first_true, OutputIterator2 d_first_false, UnaryPredicate p) { while (first != last) { if (p(*first)) { *d_first_true = *first; ++d_first_true; } else { *d_first_false = *first; ++d_first_false; } ++first; } return pair<OutputIterator1, OutputIterator2>(d_first_true, d_first_false); } |
[edit] Example
#include <iostream> #include <algorithm> #include <utility> using namespace std; int main() { int arr [10] = {1,2,3,4,5,6,7,8,9,10}; int true_arr [5] = {0}; int false_arr [5] = {0}; partition_copy(std::begin(arr), std::end(arr), std::begin(true_arr),std::begin(false_arr), [] (int i) {return i > 5;}); cout << "true_arr: "; for (auto it = std::begin(true_arr); it != std::end(true_arr); ++it) cout << *it << ' '; cout << '\n'; cout << "false_arr: "; for (auto it = std::begin(false_arr); it != std::end(false_arr); ++it) cout << *it << ' '; cout << '\n'; return 0; }
Output:
true_arr: 6 7 8 9 10 false_arr: 1 2 3 4 5
[edit] See also
|
divides a range of elements into two groups (function template) |
|
|
divides elements into two groups while preserving their relative order (function template) |
|