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  1. #include <string>
  2. #include <vector>
  3. #include <algorithm>
  4. #include <iostream>
  5. #include <ctime>
  6.  
  7. class SimpleObject 
  8. {
  9.     int _int;
  10.     float _float;
  11.  
  12. public:
  13.     SimpleObject() : _int(0), _float(0.0f) {}
  14.  
  15.     int GetInt() { return _int; }
  16.     float GetFloat() { return _float; }
  17.  
  18.     void incrementInt() { ++_int; }
  19.     void incrementFloat() { _float += 1.0f; }
  20. };
  21.  
  22. std::size_t getCount(const std::string& prompt)
  23. {
  24.     std::string Input;
  25.  
  26.     std::cout << prompt << "\n> ";
  27.  
  28.     std::getline(std::cin, Input);
  29.  
  30.     if (Input == "exit")
  31.         return 0;
  32.  
  33.     return std::stoi(Input);
  34. }
  35.  
  36. void doForLoop(std::vector<SimpleObject>& v, std::size_t iterations)
  37. {
  38.     for (std::size_t i = 0; i < iterations; ++i)
  39.     {
  40.         for (auto it = v.begin(); it != v.end(); ++it)
  41.         {
  42.             it->incrementFloat();
  43.             it->incrementInt();
  44.         }
  45.     }
  46. }
  47.  
  48. void doForEach(std::vector<SimpleObject>& v, std::size_t iterations)
  49. {
  50.     for (std::size_t i = 0; i < iterations; ++i)
  51.         for_each(v.begin(), v.end(), [](SimpleObject& o) { o.incrementFloat(); o.incrementInt(); });
  52. }
  53.  
  54. void doRangedFor(std::vector<SimpleObject>& v, std::size_t iterations)
  55. {
  56.     for (std::size_t i = 0; i < iterations; ++i)
  57.         for (auto & e : v)
  58.             e.incrementFloat(), e.incrementInt();
  59. }
  60.  
  61. using func_type = void(*)(std::vector<SimpleObject>&, std::size_t);
  62. void test(const std::string& testName, func_type testme, std::size_t iterations, std::size_t objects)
  63. {
  64.     std::vector<SimpleObject> v(objects);
  65.  
  66.     clock_t begin = clock();
  67.     testme(v, iterations);
  68.     clock_t end = clock();
  69.  
  70.     std::cout << "Test \"" << testName << "\" took " << (float(end) - begin) / CLOCKS_PER_SEC << " seconds.\n";
  71. }
  72.  
  73.  
  74. int main(int argc, char** argv) 
  75. {
  76.     std::size_t nIterations;
  77.     std::size_t nObjects;
  78.  
  79.     do 
  80.     {
  81.         nIterations = getCount("Enter the number of iterations:");
  82.         nObjects = getCount("Enter the number of objects in the container:");
  83.  
  84.         if (nIterations && nObjects)
  85.         {
  86.             std::cout << "\n\nWe will be performing " << nIterations << " iterations on a container holding ";
  87.             std::cout << nObjects << " objects.\n";
  88.  
  89.             test("for loop", doForLoop, nIterations, nObjects);
  90.             test("for each", doForEach, nIterations, nObjects);
  91.             test("ranged for", doRangedFor, nIterations, nObjects);
  92.         }
  93.     } while (nIterations && nObjects);
  94. }
Success #stdin #stdout 2.08s 3436KB
comments (?)
stdin
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1000000
500
0
0
stdout
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Enter the number of iterations:
> Enter the number of objects in the container:
> 

We will be performing 1000000 iterations on a container holding 500 objects.
Test "for loop" took 0.69 seconds.
Test "for each" took 0.7 seconds.
Test "ranged for" took 0.69 seconds.
Enter the number of iterations:
> Enter the number of objects in the container:
>
https://ideone.com/NXfPh5
language:
C++14 (gcc 8.3)
created:
10 years ago
visibility:
public

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