Defined in header <algorithm> | ||
---|---|---|
template< class RandomIt > void random_shuffle( RandomIt first, RandomIt last ); | (1) | (until C++17) (deprecated in C++14) |
(2) | ||
template< class RandomIt, class RandomFunc > void random_shuffle( RandomIt first, RandomIt last, RandomFunc& r ); | (until C++11) | |
template< class RandomIt, class RandomFunc > void random_shuffle( RandomIt first, RandomIt last, RandomFunc&& r ); | (since C++11) (until C++17) (deprecated in C++14) | |
template< class RandomIt, class URBG > void shuffle( RandomIt first, RandomIt last, URBG&& g ); | (3) | (since C++11) |
Reorders the elements in the given range [first, last)
such that each possible permutation of those elements has equal probability of appearance.
std::rand
is often used.r
. g
.first, last | - | the range of elements to shuffle randomly |
r | - | function object returning a randomly chosen value of type convertible to std::iterator_traits<RandomIt>::difference_type in the interval [0,n) if invoked as r(n) |
g | - | a UniformRandomBitGenerator whose result type is convertible to std::iterator_traits<RandomIt>::difference_type |
Type requirements | ||
-RandomIt must meet the requirements of ValueSwappable and RandomAccessIterator . |
||
-std::remove_reference_t<URBG> must meet the requirements of UniformRandomBitGenerator . |
(none).
Linear in the distance between first
and last
.
The following code randomly shuffles the integers 1..10:
#include <random> #include <algorithm> #include <iterator> #include <iostream> int main() { std::vector<int> v = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}; std::random_device rd; std::mt19937 g(rd()); std::shuffle(v.begin(), v.end(), g); std::copy(v.begin(), v.end(), std::ostream_iterator<int>(std::cout, " ")); std::cout << "\n"; }
Possible output:
generates the next greater lexicographic permutation of a range of elements (function template) |
|
generates the next smaller lexicographic permutation of a range of elements (function template) |
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