generic_list_sort3.cpp

Shows how to use xtd::collections::generic::list::sort method.

#include <xtd/xtd>
 
struct my_own_descending_comparer : icomparer<int> {
  [[nodiscard]] auto compare(const int& x, const int& y) const -> int override {return x > y ? -1 : x < y ? 1 : 0;}
};
 
auto main() -> int {
  auto items = list {10, 6, 5, 7, 8, 2, 9, 3, 1, 4};
  
  // C++ standard
  //items.sort(2, 6, [](auto&& a, auto&& b) {return a < b;});
  items.sort(2, 6, _1 < _2);
  println("ascending sorted items = {}", items);
  //items.sort(2, 6, [](auto&& a, auto&& b) {return a > b;});
  items.sort(2, 6, _1 > _2);
  println("descending sorted items = {}", items);
  println();
  
  // C++ modern with ordering
  //items.sort(2, 6, [](auto&& a, auto&& b) {return a <=> b;});
  items.sort(2, 6, _1 <=> _2);
  println("ascending sorted items = {}", items);
  //items.sort(2, 6, [](auto&& a, auto&& b) {return a <=> b == std::strong_ordering::greater;});
  items.sort(2, 6, _1 <=> _2 == std::strong_ordering::greater);
  println("descending sorted items = {}", items);
  println();
  
  // C# style
  //items.sort(2, 6, [](auto&& a, auto&& b) {return a > b ? 1 : a < b ? -1 : 0;});
  items.sort(2, 6, if_then_else(_1 > _2, 1, if_then_else(_1 < _2, -1, 0)));
  println("ascending sorted items = {}", items);
  //items.sort(2, 6, [](auto&& a, auto&& b) {return a > b ? -1 : a < b ? 1 : 0;});
  items.sort(2, 6, [](auto&& a, auto&& b) {return a > b ? -1 : a < b ? 1 : 0;});
  println("descending sorted items = {}", items);
  println();
 
  // C# style with comparer
  items.sort(2, 6, comparer<int>::default_comparer);
  println("ascending sorted items = {}", items);
  items.sort(2, 6, my_own_descending_comparer {});
  println("descending sorted items = {}", items);
  println();
}
 
// This code produces the following output :
//
// ascending sorted items = [10, 6, 2, 3, 5, 7, 8, 9, 1, 4]
// descending sorted items = [10, 6, 9, 8, 7, 5, 3, 2, 1, 4]
//
// ascending sorted items = [10, 6, 2, 3, 5, 7, 8, 9, 1, 4]
// descending sorted items = [10, 6, 9, 8, 7, 5, 3, 2, 1, 4]
//
// ascending sorted items = [10, 6, 2, 3, 5, 7, 8, 9, 1, 4]
// descending sorted items = [10, 6, 9, 8, 7, 5, 3, 2, 1, 4]
//
// ascending sorted items = [10, 6, 2, 3, 5, 7, 8, 9, 1, 4]
// descending sorted items = [10, 6, 9, 8, 7, 5, 3, 2, 1, 4]
//