Second issue is that I am able to get rid of the ':' char in the time but now I am trying to convert it to a int. I have used a few ways and after reading several forums and googling my way through it, it comes back to std::stoi. However it is simply not working. Am I using it wrong? I thought it could be the way I was combining char but string are mutable and I never had a issue combining string like this in the past.
The stox() functions require a C++11 standard compiler, are you sure you're compiling with a compliant compiler? Why are you storing these entries into a string instead of storing them into integers when you process the file?

Code:
    for (int i=0; i<sizeof(vtime); i++) {
        if (vtime[i]==':') {
            vtime[i]=' ';
        }
    }
What is a vtime? Is it a std::string, a C-string, what? If it's a std::string then the sizeof() operator is probably not doing what you think. And if it isn't a std::string why?

If vtime is a std::string I recommend you use a stringstream to process the string to convert the individual elements to the int. I've already shown you a way of doing this in one of your other topics.

And again like most of your posts you have failed to provide all the relevant code which makes this all a guessing game.

I am trying to figure out a way to sort them in order by licensePlates and camera order 1-5 so I can calculate their speed.
What have you tried?

Jim