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  1. #include <vector>
  2. #include <string>
  3. #include <chrono>
  4. #include <iostream>
  5. #include <random>
  6. #include <algorithm>
  7.  
  8. using namespace std;
  9.  
  10. struct citizen_t {
  11.     string first_name;
  12.     string last_name;
  13.     int salary;
  14.     int age;
  15. };
  16.  
  17. struct soa_citizens_t {
  18.     vector<string> first_names;
  19.     vector<string> last_names;
  20.     vector<int> salary;
  21.     vector<int> age;
  22.  
  23.     void resize( size_t n ) {
  24.         first_names.resize( n );
  25.         last_names.resize( n );
  26.         salary.resize( n );
  27.         age.resize( n );
  28.     }
  29. };
  30.  
  31. int main() {
  32.     using clock_t = chrono::high_resolution_clock;
  33.  
  34.     size_t count = 300'000'000;
  35.     uniform_int_distribution<int> salary_dist( 0, 10000 );
  36.  
  37.     chrono::duration<double> aos_duration;
  38.     chrono::duration<double> soa_duration;
  39.  
  40.     int aos_avg = 0;
  41.     int soa_avg = 0;
  42.  
  43.     // Array of Structures
  44.     {
  45.         const auto seed_val = mt19937::default_seed;
  46.         mt19937 rng( seed_val );
  47.  
  48.         vector<citizen_t> aos_citizens;
  49.         aos_citizens.resize( count );
  50.         generate_n( aos_citizens.data(), count, [&]() { citizen_t c; c.salary = salary_dist( rng ); return c; } );
  51.  
  52.         auto start = clock_t::now();
  53.  
  54.         int avg = 0;
  55.         int t = 1;
  56.         for ( auto & c : aos_citizens ) {
  57.             avg += (c.salary - avg) / t;
  58.             ++t;
  59.         }
  60.  
  61.         auto finish = clock_t::now();
  62.         aos_duration = finish - start;
  63.         aos_avg = avg;
  64.     }
  65.  
  66.     // Structure of Arrays
  67.     {
  68.         const auto seed_val = mt19937::default_seed;
  69.         mt19937 rng( seed_val );
  70.  
  71.         soa_citizens_t soa_citizens;
  72.         soa_citizens.resize( count );
  73.         generate_n( soa_citizens.salary.data(), count, [&]() { return salary_dist( rng ); } );
  74.  
  75.         auto start = clock_t::now();
  76.  
  77.         int avg = 0;
  78.         int t = 1;
  79.         for ( auto salary : soa_citizens.salary ) {
  80.             avg += (salary - avg) / t;
  81.             ++t;
  82.         }
  83.  
  84.         auto finish = clock_t::now();
  85.         soa_duration = finish - start;
  86.         soa_avg = avg;
  87.     }
  88.  
  89.     cout << "AoS (" << aos_avg << ") in " << aos_duration.count() << " seconds" << std::endl;
  90.     cout << "SoA (" << soa_avg << ") in " << soa_duration.count() << " seconds" << std::endl;
  91.  
  92.     return 0;
  93. }
  94.  
Success #stdin #stdout 0.02s 3476KB
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stdin
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Standard input is empty
stdout
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AoS (5010) in 0.00252983 seconds
SoA (5010) in 0.00248755 seconds
https://ideone.com/QNqKpD
language:
C++14 (gcc 8.3)
created:
8 years ago
visibility:
public

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