56 lines
1.7 KiB
C++
56 lines
1.7 KiB
C++
//===----------------------------------------------------------------------===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is dual licensed under the MIT and the University of Illinois Open
|
|
// Source Licenses. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
// UNSUPPORTED: c++98, c++03, c++11, c++14
|
|
|
|
// <algorithm>
|
|
|
|
// template <class PopulationIterator, class SampleIterator, class Distance,
|
|
// class UniformRandomNumberGenerator>
|
|
// SampleIterator sample(PopulationIterator first, PopulationIterator last,
|
|
// SampleIterator out, Distance n,
|
|
// UniformRandomNumberGenerator &&g);
|
|
|
|
#include <algorithm>
|
|
#include <random>
|
|
#include <cassert>
|
|
|
|
#include "test_iterators.h"
|
|
|
|
// Stable if and only if PopulationIterator meets the requirements of a
|
|
// ForwardIterator type.
|
|
template <class PopulationIterator, class SampleIterator>
|
|
void test_stability(bool expect_stable) {
|
|
const unsigned kPopulationSize = 100;
|
|
int ia[kPopulationSize];
|
|
for (unsigned i = 0; i < kPopulationSize; ++i)
|
|
ia[i] = i;
|
|
PopulationIterator first(ia);
|
|
PopulationIterator last(ia + kPopulationSize);
|
|
|
|
const unsigned kSampleSize = 20;
|
|
int oa[kPopulationSize];
|
|
SampleIterator out(oa);
|
|
|
|
std::minstd_rand g;
|
|
|
|
const int kIterations = 1000;
|
|
bool unstable = false;
|
|
for (int i = 0; i < kIterations; ++i) {
|
|
std::sample(first, last, out, kSampleSize, g);
|
|
unstable |= !std::is_sorted(oa, oa + kSampleSize);
|
|
}
|
|
assert(expect_stable == !unstable);
|
|
}
|
|
|
|
int main() {
|
|
test_stability<forward_iterator<int *>, output_iterator<int *> >(true);
|
|
test_stability<input_iterator<int *>, random_access_iterator<int *> >(false);
|
|
}
|