static void Main()
    {
        Debug.Assert(PerformAction(), "Could not perform action");

        StudentGradesCalculator calc = new StudentGradesCalculator(new int[] { 6, 5, 5, 4, 6, 6, 5, 6 });
        Console.WriteLine(calc.GetAverageStudentGrade());

        calc = new StudentGradesCalculator(new int[] { });
        Console.WriteLine(calc.GetAverageStudentGrade());
    }
    static void Main()
    {
        Debug.Assert(PerformAction(), "Could not perform action");

        StudentGradesCalculator calc = new StudentGradesCalculator(new int[] { 6, 5, 5, 4, 6, 6, 5, 6 });

        Console.WriteLine(calc.GetAverageStudentGrade());

        calc = new StudentGradesCalculator(new int[] { });
        Console.WriteLine(calc.GetAverageStudentGrade());
    }