How do I change a vector to a vector of pointers in C++?

Question

I have been having this issue and I can't seem to find any resources that help me.

Basically, I have to change vector<User> to be a vector<User*> in this function:

void promptUserAction(vector<User> &players, int playernumber, const Room rooms[], string &strCh,BadGuy bad)
{
    // tell user where they are and describes the room
    cout << (players)[playernumber] << " you are currently in " << rooms[(players)[playernumber].getIndexofCurrentRoom()]
         << endl;
    if ((players)[playernumber].getIndexofCurrentRoom()==bad.getIndexCurrentRoom())
    {
        cout<<"There is a bad guy ("+bad.getName()+") also in the room."<<endl;
    }
    //prompt user for choice
    cout << "What would you like to do?" << endl << "**********************" << endl;
    cin >> strCh;
}

I can't figure out how to call the function in my main() function correctly.

do {
    promptUserAction(players, User::IndNextUser, rooms, UserAction, badGuy1);

Answer 1

There is no need to wrap the players parameter in parenthesis like (players) whenever you refer to it. Change (players)[playernumber] to players[playernumber] .

In any case, nothing in the code you have shown wants a vector<User*> , so why do you think you need this conversion? If you really need it (in code you have not shown), then the only way to "convert" a vector<T> into a vector<T*> is to create a new vector and push the addresses of the 1st vector 's elements into it, eg:

vector<T> vec;
...
std::vector<T*> dest;
dest.reserve(vec.size());
for(auto &elem : vec) {
    dest.push_back(&elem);
}

Alternatively:

vector<T> vec;
...
std::vector<T*> dest(vec.size());
std::transform(vec.begin(), vec.end(), dest.begin(),
    [](auto &elem){ return &elem; }
);