Flag.getNextNumber C# (CSharp) Method

    private int getNextNumber()
    {
        if(num_list.Count == 0)
            return 1;

        int max = 0;
        foreach(int i in num_list)
        {
            if(i > max)
                max = i;
        }

        for(int i = 1; i < max; i++)
        {
            if(!num_list.Contains(i))
                return i;
        }

        return max + 1;
    }