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  1. #include <chrono>
  2. #include <cstdint>
  3. #include <iostream>
  4. #include <random>
  5. #include <vector>
  6.  
  7. using accu_t = std::uint32_t;
  8. using element_t = std::uint32_t;
  9. std::size_t const num_elements = 10000000;
  10.  
  11. int main()
  12. {
  13. 	std::vector<element_t> elements;
  14. 	elements.reserve(num_elements);
  15. 	std::uniform_int_distribution<element_t> distribution;
  16. 	std::mt19937_64 engine;
  17. 	for (std::size_t i = 0; i != num_elements; ++i)
  18. 	{
  19. 		elements.push_back(distribution(engine));
  20. 	}
  21.  
  22. #ifdef USE_PTR
  23. 	std::vector<element_t *> ptrs;
  24. 	ptrs.reserve(num_elements);
  25. 	for (auto & element : elements) ptrs.push_back(&element);
  26. #endif
  27.  
  28. 	accu_t sum = 0;
  29. 	auto start = std::chrono::steady_clock::now();
  30.  
  31. #ifdef USE_PTR
  32. 	for (auto ptr : ptrs) sum += *ptr;
  33. #else
  34. 	for (auto element : elements) sum += element;
  35. #endif
  36.  
  37. 	auto stop = std::chrono::steady_clock::now();
  38. 	auto ms = std::chrono::duration_cast<std::chrono::milliseconds>(stop - start);
  39. 	std::cout << "sum: " << sum << "\n";
  40. 	std::cout << ms.count() << "ms\n";
  41. }
Success #stdin #stdout 0.51s 3344KB
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Standard input is empty
stdout
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sum: 2517582001
15ms
https://ideone.com/xIV3f9
language:
C++14 (gcc 8.3)
created:
9 years ago
visibility:
public

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