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  1. #include <iostream>
  2. #include <chrono>
  3. #include <type_traits>
  4. #include <stdlib.h>
  5. #include <time.h> 
  6.  
  7. using namespace std;
  8. using namespace std::chrono;
  9.  
  10. struct Test
  11. {
  12.   Test(int a, int b, int c) : a(a), b(b), c(c) { }
  13.   int a, b, c;
  14. };
  15.  
  16. const int NUMBER = 100000000;
  17.  
  18. int main()
  19. {
  20.   cout << "Creating " << NUMBER << " objects" << endl;
  21.  
  22.   high_resolution_clock::time_point start, end;
  23.   start = high_resolution_clock::now();
  24.  
  25.   for(int i = 0; i < NUMBER; ++i)
  26.   {
  27.     Test *t = new Test(1, 2, 3);
  28.     /* ... */
  29.     delete t;
  30.   }
  31.  
  32.   end = high_resolution_clock::now();
  33.   auto duration = duration_cast<milliseconds>(end - start).count();
  34.   cout << "Normal: " << duration << "ms" << endl;
  35.  
  36.  
  37.   start = high_resolution_clock::now();
  38.  
  39.   std::aligned_storage<sizeof(Test), alignof(Test)>::type als[1];
  40.   for(int i = 0; i < NUMBER; ++i)
  41.   {
  42.     Test *t = new(als) Test(1, 2, 3);
  43.     /* ... */
  44.     t->~Test();
  45.   }
  46.  
  47.   end = high_resolution_clock::now();
  48.   duration = duration_cast<milliseconds>(end - start).count();
  49.   cout << "Placement: " << duration << "ms" << endl;
  50.  
  51.   return 0;
  52. }
Success #stdin #stdout 1.74s 4368KB
comments (?)
stdin 
Standard input is empty
stdout 
Creating 100000000 objects
Normal: 1737ms
Placement: 0ms
https://ideone.com/aMCs5I
Advanced CPP: Memory usage
Placement new optimalization
language:
C++14 (gcc 8.3)
created:
4 years ago
visibility:
secret

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