#include <algorithm>

#include <chrono>

#include <random>

#include <ratio>

#include <stddef.h>

#include <stdio.h>

#include <vector>

#include <execution>

const size_t testSize = 1'000'000;

const int iterationCount = 5;

void print_results(const char *const tag, const std::vector<double> &sorted,

std::chrono::high_resolution_clock::time_point startTime,

std::chrono::high_resolution_clock::time_point endTime) {

printf("%s: Lowest: %g Highest: %g Time: %fms\n", tag, sorted.front(),

sorted.back(),

std::chrono::duration_cast<std::chrono::duration<double, std::milli>>(

endTime - startTime)

.count());

}

int main() {

// generate some random doubles:

printf("Testing with %zu doubles...\n", testSize);

std::random_device rd;

std::vector<double> doubles(testSize);

for (auto &d : doubles) {

d = static_cast<double>(rd());

}

// time how long it takes to sort them:

for (int i = 0; i < iterationCount; ++i) {

std::vector<double> sorted(doubles);

const auto startTime = std::chrono::high_resolution_clock::now();

std::sort(std::execution::seq, sorted.begin(), sorted.end());

const auto endTime = std::chrono::high_resolution_clock::now();

print_results("Serial STL ", sorted, startTime, endTime);

}

for (int i = 0; i < iterationCount; ++i) {

std::vector<double> sorted(doubles);

const auto startTime = std::chrono::high_resolution_clock::now();

// same sort call as above, but with par_unseq:

std::sort(std::execution::par, sorted.begin(), sorted.end());

const auto endTime = std::chrono::high_resolution_clock::now();

// in our output, note that these are the parallel results:

print_results("Parallel STL", sorted, startTime, endTime);

}

}