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  1. #include <iostream>
  2. #include <array>
  3. #include <random>
  4. #include <numeric>
  5. #include <algorithm>
  6. #include <iterator>
  7.  
  8. template <class Result, class It>
  9. Result avg(It begin,
  10.            It end)
  11. {
  12.   auto sum = std::accumulate(begin,
  13.                              end,
  14.                              Result{});
  15.   auto size = std::distance(begin, end);
  16.   return sum / size;
  17. }
  18.  
  19. thread_local std::mt19937 gen{std::random_device{}()};
  20.  
  21. // https://d...content-available-to-author-only...q.cc/post/180/nie-uzywaj-rand-cxx-ma-random/
  22. template<typename T>
  23. T random(T min, T max) {
  24.     using dist = std::conditional_t<
  25.         std::is_integral<T>::value,
  26.         std::uniform_int_distribution<T>,
  27.         std::uniform_real_distribution<T>
  28.     >;
  29.     return dist{min, max}(gen);
  30. }
  31.  
  32. template <class It, class T = typename std::iterator_traits<It>::value_type>
  33. void fillWithRandomData(It begin,
  34.                         It end,
  35.                         T min,
  36.                         T max)
  37. {
  38.   std::generate(begin, end, [&]() {
  39.                   return random(min, max);
  40.                 });
  41. }
  42.  
  43. template <class It, class UnaryPredicate>
  44. void print(It begin,
  45.            It end,
  46.            UnaryPredicate pred)
  47. {
  48.   std::copy_if(begin,
  49.                end,
  50.                std::ostream_iterator<typename std::iterator_traits<It>::value_type>(std::cout, "\n"),
  51.                pred);
  52. }
  53.  
  54. template <class It>
  55. void printMinMax(It begin,
  56.                  It end)
  57. {
  58.   auto minmax = std::minmax_element(begin, end);
  59.   std::cout
  60.     << "Min: " << *(minmax.first) << "\n"
  61.     << "Max: " << *(minmax.second) << "\n";
  62.  
  63. }
  64.  
  65. template <class It>
  66. void printMatrixMinMax(It begin,
  67.                        It end)
  68. {
  69.   using Type = typename std::iterator_traits<It>::value_type;
  70.   std::vector<typename Type::value_type> buffer;
  71.   std::for_each(begin,
  72.                 end,
  73.                 [&](auto elem) {
  74.                   auto minmax = std::minmax_element(elem.begin(), elem.end());
  75.                   buffer.push_back(*(minmax.first));
  76.                   buffer.push_back(*(minmax.second));
  77.                 });
  78.  
  79.   auto minmax = std::minmax_element(buffer.begin(), buffer.end());
  80.   std::cout
  81.     << "Min = " << *(minmax.first) << "\n"
  82.     << "Max = " << *(minmax.second) << "\n";
  83. }
  84.  
  85. template <class Result, class It>
  86. Result sumDiagonalMatrix(It begin,
  87.                          It end)
  88. {
  89.   Result result{};
  90.   auto size = std::distance(begin, end);
  91.   auto iter = begin;
  92.   for (auto i = 0; i < size; ++i) {
  93.     auto tmp = *iter;
  94.     result += *(std::next(tmp.begin(), i));
  95.     std::advance(iter, 1);
  96.   }
  97.   return result;
  98. }
  99.  
  100. int main()
  101. {
  102.   // 1.
  103.   std::array<int, 8> foo {1, 2, 3, 4, 5, 6, 7, 8};
  104.   auto average = avg<double>(foo.begin(), foo.end());
  105.   std::cout << "Avg = " << average << "\n";
  106.   if (average < 5.0) {
  107.     std::cout << "< 5.0\n";
  108.   } else if (average > 5.0) {
  109.     std::cout << "> 5.0\n";
  110.   } else {
  111.     std::cout << "== 5.0\n";
  112.   }
  113.  
  114.   // 2.
  115.   std::array<int, 10> bar;
  116.   fillWithRandomData(bar.begin(),
  117.                      bar.end(),
  118.                      1,
  119.                      500);
  120.   print(bar.begin(),
  121.         bar.end(),
  122.         [](auto elem) {
  123.           return elem % 6 == 0;
  124.         });
  125.  
  126.   // 3.
  127.   std::array<int, 20> simple;
  128.   fillWithRandomData(simple.begin(),
  129.                      simple.end(),
  130.                      10,
  131.                      50);
  132.   printMinMax(simple.begin(), simple.end());
  133.  
  134.   // 5.
  135.   std::array<std::array<int, 3>, 3> matrix;
  136.  
  137.   for (auto& elem : matrix) {
  138.     fillWithRandomData(elem.begin(),
  139.                        elem.end(),
  140.                        0,
  141.                        100);
  142.   }
  143.  
  144.   printMatrixMinMax(matrix.begin(), matrix.end());
  145.  
  146.   // 6.
  147.   std::array<std::array<int, 3>, 3> matrix2;
  148.  
  149.   for (auto& elem : matrix2) {
  150.     fillWithRandomData(elem.begin(),
  151.                        elem.end(),
  152.                        0,
  153.                        100);
  154.   }
  155.  
  156.   auto sum = sumDiagonalMatrix<int>(matrix2.begin(),
  157.                                     matrix2.end());
  158.   std::cout << "Diagonal sum = " << sum << "\n";
  159. }
Success #stdin #stdout 0s 4476KB
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Avg = 4.5
< 5.0
462
42
36
Min: 12
Max: 50
Min = 4
Max = 92
Diagonal sum = 204
https://ideone.com/gfVobe
language:
C++14 (clang 8.0)
created:
4 years ago
visibility:
public

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