From the archives. A challenge with this is (I think?) Javascript overloads their tolower equivalent to take either strings or characters. This is more testing familiarity with language features (do you do this, or do you use ASCII tables — which I guess isn’t unicode-friendly — or something else?) than anything else. Not a terrible question, just a correct answer doesn’t say much about the candidate/student.

class Solution {
public:
    string toLowerCase(string str) {
        string v;
        for (auto&& c : str) {
            v.push_back(std::tolower(c));
        }
        return v;
        // Maybe this is an excuse for some sanity checking, as well as destroying the input parameter,
        // etc.
    }
};

Nevertheless, it’s a string question, so it lives here.