Function problem_19

examples/99_problems.cpp:163–166

P19 (**) Rotate a list N places to the left.

// P19 (**) Rotate a list N places to the left.
void problem_19()
{
    print_result(apply_function_n_times(rotate_left<Ints>, 3, xs));
}

// P20 (*) Remove the K'th element from a list.
void problem_20()