you could move the vector to count. Each line read in by getline could be added to the vector. If you need to edit the strings inside random, you could pass the vector by reference, or const reference if you don't.
edit: Also, if you just want to get a random string from the vector you could do
I've also seen something called random_shuffle talked about before that could randomize the vector. I haven't dealt with it myself, and don't know if it's standard.
vectorname[rand() % vectorname.size()]