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  1. #include <iostream>
  2. #include <vector>
  3. #include <chrono>
  4. #include <cstring>
  5.  
  6. const int SIZE = 1024*1024;
  7.  
  8. void WithArray()
  9. {
  10. 	using namespace std;
  11. 	char* a = new char[SIZE];
  12. 	auto b = &a[0];
  13. 	auto e = &a[SIZE];
  14.  
  15. 	memset(a, 0, SIZE);
  16. 	int total=0;
  17.  
  18. 	auto begin = chrono::system_clock::now();
  19. 	for(int c=0; c<100; c++) {
  20. 		for(auto p=b; p<e;) {
  21. 			total += *p++;
  22. 		}
  23. 	}
  24. 	auto end  = chrono::system_clock::now();
  25. 	cout << total << ":" << chrono::duration_cast<chrono::milliseconds>(end-begin).count() << endl;
  26. 	delete[] a;
  27. }
  28.  
  29. void WithVector()
  30. {
  31. 	using namespace std;
  32. 	vector<char> a(SIZE);
  33. 	auto b = a.begin();
  34. 	auto e = a.end();
  35. 	int total=0;
  36.  
  37. 	auto begin = chrono::system_clock::now();
  38. 	for(int c=0; c<100; c++) {
  39. 		for(auto it=b; it<e;) {
  40. 			total += *it++;
  41. 		}
  42. 	}
  43. 	auto end  = chrono::system_clock::now();
  44. 	cout << total << ":" << chrono::duration_cast<chrono::milliseconds>(end-begin).count() << endl;
  45. }
  46.  
  47. int main()
  48. {
  49. 	WithArray();
  50. 	WithVector();
  51. 	WithArray();
  52. 	WithVector();
  53. }
  54.  
Success #stdin #stdout 0.51s 3300KB
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https://ideone.com/VQdY0v
language:
C++14 (gcc 8.3)
created:
11 years ago
visibility:
public

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