exercise 9.31 (a)

ex9_31.cpp

#include <iostream>
#include <forward_list>

int main ()
{
    std::forward_list <int> v1 = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};

    auto curr = v1.begin();
    auto prev = v1.before_begin ();

    while (curr != v1.end()) {
        if (*curr % 2) {
           prev = v1.insert_after (prev, *curr);
           ++curr;
           ++prev;

        } else {
           curr = v1.erase_after(prev);
        }
    }

    for (auto it : v1)
        std::cout << it << " ";

    return 0;
}