charlist.cpp

#include <memory>
#include <string>

struct CharList {
    char c;
    std::unique_ptr<CharList> next;
    explicit CharList(char c) : c(c) {}
};

CharList make_list(const std::string &s) {
    CharList res{'a'};
    auto *tail = &res.next;
    for (char c : s) {
        *tail = std::make_unique<CharList>(c);
        tail = &(*tail)->next;
    }
    return res;
}