Function problem_15

examples/99_problems.cpp:137–140

P15 (**) Replicate the elements of a list a given number of times.

// P15 (**) Replicate the elements of a list a given number of times.
void problem_15()
{
    print_result(replicate_elems(3, xs));
}

// P16 (**) Drop every N'th element from a list.
void problem_16()