Dictionary in C++ using a Map with no values, only keys

Question

I'm implementing some sort of lookup for words in c++, and while the code for implementing a map is there, I wanna make sure if it works that using a map with keys and values as std::string, and using only keys as lookups without a value to return.

    std::vector< std::string> DictionLines;
    Reader DictionReader(Dictionary);
    DictionLines = DictionReader.getLines();
    std::map<std::string, std::string> DictionaryM;

    for (int t = 0; t < DictionLines.size(); ++t) {
        DictionaryM.insert(std::pair<std::string, std::string>(DictionLines.at(t), DictionLines.at(t)));
    }

This code takes in the 349900 words in a Dictionary.txt file, and stores them in the map. Each line of the dictionary is just the word to lookup; no definition or any value to associate. Which is why I think just storing a pair of the same key and value in the map is ok, and using find and first/second would also be fine? Please confirm.

Answer 1

It looks like you want std::set. It is like a map where only keys matter and you never care or use the value. To look in a dictionary represented as a std::set<std::string> for some word after a given prefix, consider lower_bound

You should look more into C++ standard containers. There are not that much choice, and you should somehow know all of them (and choose or combine the right containers for the job)