#include <numeric>
#include <iostream>

int main()
{
  double arr[] = { 1, 2, 3, 4, 5 };
  double diff[5]; 

  std::adjacent_difference(arr, arr+5, diff);

  std::cout << "Fortlaufende Differenzen von 1 2 3 4 5:\n";  
  for (auto d : diff)
  {
    std::cout << d << ' ';
  }
  std::cout << '\n';   
}