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  1. #include <iostream>
  2. #include <tuple>
  3. #include <chrono>
  4. using namespace std;
  5. using namespace std::chrono;
  6.  
  7. void safe_swap(int* a, int* b) {
  8.     if (a != b)
  9.         *b ^= *a ^= *b, *a ^= *b;
  10. }
  11. void classic_swap(int*a, int*b) {
  12.     if (a!=b) {
  13.         int tmp; 
  14.         tmp=*a;*a=*b;*b=tmp;
  15.     }   
  16. }
  17. void modern_swap(int*a, int*b) {
  18.     if (a!=b) 
  19.         tie(*a,*b)=make_pair(*b,*a);
  20. }
  21.  
  22. long long benchmark(void(*f)(int*,int*)) {
  23. 	int a,b; 
  24. 	long long mytime;
  25. 	high_resolution_clock::time_point t = high_resolution_clock::now();
  26. 	a = rand(); 
  27.  
  28. 	for (unsigned i=0; i<200000000; i++) {
  29. 		b = rand();
  30. 		f(&a,&b); 
  31. 	}
  32. 	high_resolution_clock::time_point t2 = high_resolution_clock::now();
  33. 	mytime = duration_cast<milliseconds>(t2 - t).count();
  34. 	return mytime; 
  35. }
  36.  
  37. int main() {
  38. 	auto t1 = benchmark (safe_swap);
  39. 	auto t2 = benchmark (modern_swap);
  40. 	cout << "xor:   "<<t1<<" ms" <<endl;
  41. 	cout << "modern:"<<t2<<" ms" <<endl;
  42. 	cout << "rel xor time: " << static_cast<double>(t1)/t2*100 <<"%"<<endl;
  43. 	return 0;
  44. }
Success #stdin #stdout 3.3s 15232KB
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Standard input is empty
stdout
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xor:   1708 ms
modern:1606 ms
rel xor time: 106.351%
https://ideone.com/MK6wL5
language:
C++14 (gcc 8.3)
created:
7 years ago
visibility:
public

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