using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        var students = StudentClass.students;

​

​

            IEnumerable<IGrouping<StudentClass.GradeLevel, StudentClass.Student>> group1 = from student in students

                                                                           group student by student.Year;

​

            foreach (var item in group1)

            {

                Console.WriteLine(item.Key);

                foreach (var stu in item)

                {

                    Console.WriteLine(stu.FirstName + " " + stu.LastName);

                }

                Console.WriteLine();

            }

    }

}

​

public class StudentClass

    {

​

        public enum GradeLevel { FirstYear = 1, SecondYear, ThirdYear, FourthYear };

​

        public class Student

        {

            public string FirstName { get; set; }

            public string LastName { get; set; }

            public int ID { get; set; }

            public GradeLevel Year;

            public List<int> ExamScores;

        }

​

        public static List<Student> students = new List<Student>

    {

        new Student {FirstName = "Terry", LastName = "Adams", ID = 120, 

            Year = GradeLevel.SecondYear, 

            ExamScores = new List<int>{ 99, 82, 81, 79}},

        new Student {FirstName = "Fadi", LastName = "Fakhouri", ID = 116, 

            Year = GradeLevel.ThirdYear,

            ExamScores = new List<int>{ 99, 86, 90, 94}},

        new Student {FirstName = "Hanying", LastName = "Feng", ID = 117, 

            Year = GradeLevel.FirstYear, 

            ExamScores = new List<int>{ 93, 92, 80, 87}},

        new Student {FirstName = "Cesar", LastName = "Garcia", ID = 114, 

            Year = GradeLevel.FourthYear,

            ExamScores = new List<int>{ 97, 89, 85, 82}},

        new Student {FirstName = "Debra", LastName = "Garcia", ID = 115, 

            Year = GradeLevel.ThirdYear, 

            ExamScores = new List<int>{ 35, 72, 91, 70}},

        new Student {FirstName = "Hugo", LastName = "Garcia", ID = 118, 

            Year = GradeLevel.SecondYear, 

            ExamScores = new List<int>{ 92, 90, 83, 78}},

        new Student {FirstName = "Sven", LastName = "Mortensen", ID = 113, 

            Year = GradeLevel.FirstYear, 

            ExamScores = new List<int>{ 88, 94, 65, 91}},

        new Student {FirstName = "Claire", LastName = "O'Donnell", ID = 112, 

            Year = GradeLevel.FourthYear, 

            ExamScores = new List<int>{ 75, 84, 91, 39}},

        new Student {FirstName = "Svetlana", LastName = "Omelchenko", ID = 111, 

            Year = GradeLevel.SecondYear, 

            ExamScores = new List<int>{ 97, 92, 81, 60}},

        new Student {FirstName = "Lance", LastName = "Tucker", ID = 119, 

            Year = GradeLevel.ThirdYear, 

            ExamScores = new List<int>{ 68, 79, 88, 92}},

        new Student {FirstName = "Michael", LastName = "Tucker", ID = 122, 

            Year = GradeLevel.FirstYear, 

            ExamScores = new List<int>{ 94, 92, 91, 91}},

        new Student {FirstName = "Eugene", LastName = "Zabokritski", ID = 121,

            Year = GradeLevel.FourthYear, 

            ExamScores = new List<int>{ 96, 85, 91, 60}}

    };

​

    }