// Initialise a stringstream to hold the loaded files contents.
    ostringstream fileStream;

    bool fileAccepted = false;

    // Loop until the user inputs a valid filename or type "Exit".
    do
    {
        string fileName;

        // Ask the user for a filename input for the program to load data from.
        cout << "Please enter the filname. E.g. problem_small.txt. To exit, enter 'Exit'." << endl;
        cin >> fileName;

        cin.get();

        // If the user types "Exit", exit the program.
        if (fileName == "Exit")
        {
            return 0;
        }

        // Open a ifstream with the filename from the user.
        ifstream inFile(fileName);

        // Check if the file successfully loaded. This will only pass if the user enters a file that exists.
        if (inFile)
        {
            // When the file is successfully loaded, transfer the data into the stringstream.
            fileStream << inFile.rdbuf();

            // Close the opened file.
            inFile.close();

            fileAccepted = true;
        }
        else
        {
            // Report that the file could not be loaded.
            cout << "Could not find/load file " << fileName << "." << endl;
        }

        // If the file has not been loaded, ask again. If it has been loaded, continue the program.
    } while (!fileAccepted);

    // Get the stringstream into a usable format.
    istringstream fileData(fileStream.str());