fork download

copy

#include <iostream>
#include <array>
 
template <std::size_t... Idx>
using list = std::index_sequence<Idx...> *;
 
template <std::size_t Count>
using make_indices = std::make_index_sequence<Count> *;
 
template <class T>
  constexpr void swap(T& a, T& b) noexcept {
    T t = a;
    a = b;
    b = t;
  }
 
  template <class T, std::size_t N>
  constexpr std::size_t partition(std::array<T, N> &array, std::size_t low, std::size_t high) noexcept {
    auto pivot = array[high];
    std::size_t i = low;
    for (std::size_t j = low; j < high; ++j) {
      if (array[j] <= pivot) {
        swap(array[i], array[j]);
        ++i;
      }
    }
    swap(array[i], array[high]);
    return i;
  }
 
  template<class T, std::size_t N>
  constexpr void sort(std::array<T, N>& array, std::size_t low = 0, std::size_t high = N-1) noexcept {
    if (low < high && high != ~std::size_t(0)) {
      std::size_t p = partition(array, low, high);
      sort(array, low, p-1);
      sort(array, p+1, high);
    }
  }
 
 
int main() {
	std::array<int, 4> a = {3,2,4,1};
	sort(a);
	for(int i:a){
		std::cout << i;
	}
	std::array<int, a[3]> b;
 
	// your code goes here
	return 0;
}

prog.cpp: In function ‘int main()’:
prog.cpp:47:21: error: call to non-‘constexpr’ function ‘std::array<_Tp, _Nm>::value_type& std::array<_Tp, _Nm>::operator[](std::array<_Tp, _Nm>::size_type) [with _Tp = int; long unsigned int _Nm = 4; std::array<_Tp, _Nm>::reference = int&; std::array<_Tp, _Nm>::value_type = int; std::array<_Tp, _Nm>::size_type = long unsigned int]’
  std::array<int, a[3]> b;
                     ^
prog.cpp:47:21: error: call to non-‘constexpr’ function ‘std::array<_Tp, _Nm>::value_type& std::array<_Tp, _Nm>::operator[](std::array<_Tp, _Nm>::size_type) [with _Tp = int; long unsigned int _Nm = 4; std::array<_Tp, _Nm>::reference = int&; std::array<_Tp, _Nm>::value_type = int; std::array<_Tp, _Nm>::size_type = long unsigned int]’
prog.cpp:47:22: note: in template argument for type ‘long unsigned int’
  std::array<int, a[3]> b;
                      ^

Standard output is empty