class PreviousHistory
{
    public void ViewHistory()
    {
        List<string> addGames = new();
        List<string> subGames = new();
        List<string> multGames = new();
        List<string> divGames = new();

        List<string> previousHistory = new()
        {
            "Addition Games",
            "Subtraction Games",
            "Multiplication Games",
            "Division Games"
        };

        previousHistory[1].Insert(addGames);
        previousHistory[3].Insert(subGames);
        previousHistory[5].Insert(multGames);
        previousHistory[-1].Insert(divGames);

        for (int i = 0; i < previousHistory.Count; i++)
        {
            // check if item is a string -> write to console if so
            // otherwise, iterate through sub list -> write items
        }

        Console.WriteLine("Previous Games You've Played.");
        // print games here
    }
}