using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

    }

}

​

namespace lab7

{

    class Student

    {

        private string first;

        private string last;

        private int id;

        private double gpi;

        public string First

        {

            get

            {

                return first;

            }

​

            set

            {

                first = value;

            }

        }

​

        public string Last

        {

            get

            {

                return last;

            }

​

            set

            {

                last = value;

            }

        }

​

        public int ID

        {

            get

            {

                return id;

            }

​

            set

            {

                id = value;

            }

        }

​

        public double GPI

        {

            get

            {

                return gpi;

            }

​

            set

            {

                gpi = value;

            }

        }

​

        public Student(string first, string last, int id, double gpi)

        {

            this.First = first;

            this.Last = last;

            this.ID = id;

            this.GPI = gpi;

        }

​

        public override string ToString()

        {

            return string.Format("First:{0} Last:{1} ID:{2} GPI:{3}", First, Last, ID, GPI);

        }

    }

​

    class Program

    {

        static void Main(string[] args)

        {

            Student s1 = new Student("Maha", "Muhammed", 435690032, 3.51);

            Student s2 = new Student("Nourah", "Ahmed", 436600934, 4.98);

            Student s3 = new Student("Rania", "Muhammed", 435600031, 2.5);

            Student s4 = new Student("Arwa", "Ali", 435620934, 1.98);

            Student s5 = new Student("Sarah", "Kareem", 437600042, 3.59);

            Student s6 = new Student("Shaden", "Abdullah", 438000803, 4.35);

            Student[] datasource = new Student[]{s1, s2, s3, s4, s5, s6};

            var students1 =

                from student in datasource

                orderby student.First ascending

                select student;

            Console.WriteLine("Students sorted by first name in ascending order");

            Console.WriteLine("------------------------------------------");

            foreach (var student in students1)

                Console.WriteLine(student);

            var students2 =

                from student in datasource

                orderby student.GPI descending

                select student;

            Console.WriteLine("Students sorted by GPI in descending order");

            Console.WriteLine("------------------------------------------");

            foreach (var student in students2)

                Console.WriteLine(student);

            var students3 =

                from student in datasource

                where student.GPI < 2

                select student;

            Console.WriteLine("Students whose their GPI less than 2 ");

            Console.WriteLine("------------------------------------------");

            foreach (var student in students3)

                Console.WriteLine(student);

            var students4 =

                from student in datasource

                where student.GPI <= 4.5 && student.GPI >= 3

                select student;

            Console.WriteLine("Students whose their GPI between 3.0 and 4.5 ");

            Console.WriteLine("------------------------------------------");

            foreach (var student in students4)

                Console.WriteLine(student);

            var students5 =

                from student in datasource

                where student.Last[0] == 'A'

                select student;

            Console.WriteLine("last names which start with A  ");

            Console.WriteLine("------------------------------------------");

            foreach (var student in students5)

                Console.WriteLine(student);

        }

    }

}