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  1. #include <cstdio>
  2. #include <iostream>
  3. #include <map>
  4. #include <limits>
  5.  
  6. #include "windows.h"
  7.  
  8. using namespace std;
  9.  
  10. int main()
  11. {
  12. 	LARGE_INTEGER tmp_buffer;
  13.  
  14. 	double freq;
  15. 	double ns_per_tick;
  16.  
  17. 	if (!QueryPerformanceFrequency(&tmp_buffer))
  18. 		cout << "QueryPerformanceFrequency failed\n"; 
  19.  
  20. 	freq = (double)tmp_buffer.QuadPart;
  21. 	ns_per_tick = 1E9 / freq;
  22. 	cout << "cpu freq = " << ns_per_tick << "ns" << endl;
  23.  
  24. 	int count = 1000 * 1000;
  25. 	map<__int64, int> ccnt;
  26. 	__int64 ft_wait;
  27. 	__int64 min_wait = LLONG_MAX;
  28. 	__int64 max_wait = LLONG_MIN;
  29.  
  30. 	cout << "Wait time (ns): ";
  31. 	cin >> ft_wait;
  32. 	ft_wait /= ns_per_tick;
  33.  
  34. 	for (size_t i = 0; i < count; i++)
  35. 	{
  36. 		__int64 ft_beg, ft_end;
  37. 		__int64 ft_current;
  38.  
  39. 		QueryPerformanceCounter(&tmp_buffer);
  40. 		ft_beg = tmp_buffer.QuadPart;
  41.  
  42. 		do
  43. 		{
  44. 			QueryPerformanceCounter(&tmp_buffer);
  45. 			ft_current = tmp_buffer.QuadPart;
  46. 		} while ((ft_current - ft_beg) < ft_wait);
  47.  
  48. 		ft_end = ft_current;
  49. 		__int64 ft_real_wait = ft_end - ft_beg;
  50.  
  51. 		min_wait = min_wait > ft_real_wait ? ft_real_wait : min_wait;
  52. 		max_wait = max_wait < ft_real_wait ? ft_real_wait : max_wait;
  53.  
  54. 		if (ccnt.find(ft_real_wait) != ccnt.end())
  55. 			ccnt[ft_real_wait]++;
  56. 		else
  57. 			ccnt.insert(pair<__int64, int>(ft_real_wait, 1));
  58. 	}
  59.  
  60. 	for (auto i = ccnt.begin(); i != ccnt.end(); ++i)
  61. 		cout << "計時長度" << (int)(i->first * ns_per_tick) << "發生 " << i->second << " 次" << endl;
  62.  
  63. 	cout << "計數次數" << count << " 次" << endl;
  64. 	cout << "最小計時長度" << min_wait * ns_per_tick << "ns" << endl;
  65. 	cout << "最大計時長度" << max_wait * ns_per_tick << "ns" << endl;
  66.  
  67. 	getchar();
  68. 	getchar();
  69. }
Compilation error #stdin compilation error #stdout 0s 0KB
comments (?)
stdin
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Standard input is empty
compilation info 
prog.cpp:6:10: fatal error: windows.h: No such file or directory
 #include "windows.h"
          ^~~~~~~~~~~
compilation terminated.
stdout
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Standard output is empty
https://ideone.com/gXjVF0
language:
C++ (gcc 8.3)
created:
5 years ago
visibility:
public

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