using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

class StudentInfo : IComparable
{
    public StudentInfo(string ln, string fn, int id, string a)
    {
        lastName = ln; firstName = fn; idNumber = id; address = a;
    }

    public int CompareTo(object obj)
    {
        StudentInfo s = (StudentInfo)obj;

        if (s.ID < ID)
            return 1;
        else if (s.ID > ID)
            return -1;
        else
            return 0;
    }

    public override string ToString()
    {
        return firstName+" "+lastName+" "+idNumber+" " +address;
    }

    public string FirstName
    {
        get { return firstName; }
        set { firstName = value; }
    }

    public string LastName
    {
        get { return lastName; }
        set { lastName = value; }
    }

    public string Address
    {
        get { return address; }
        set { address = value; }
    }

    public int ID
    {
        get { return idNumber; }
        set { idNumber = value; }
    }

    private string firstName;
    private String lastName;
    private int idNumber;
    private string address;


    
}


public class LINQtoObjectArray
{
    static void Main(string[] args)
    {
        StudentInfo[] students ={
          new StudentInfo("Smith", "John", 12345, "5 Bournbrook Rd"),
          new StudentInfo("Brown", "Alan", 23412, "Dawlish Rd"),
          new StudentInfo("Smith","Colin", 41253, "23 Bristol Rd"), 
          new StudentInfo("Hughes", "Richard", 52314, "18 Prichatts Rd"),
          new StudentInfo("Murphy", "Paul", 16352, "37 College Rd") };    

        // Filter a range of ID numbers
        var idRange=
            from s in students
            where s.ID>19999 && s.ID<=49999
            select s;

        //PrintArray(idRange,"Students with ID in Range 2000 to 4999");

        // Order by last name and then first name
        var nameSorted =
            from s in students
            orderby s.LastName, s.FirstName
            select s;

        //PrintArray(nameSorted, "Students sorted in last name, first name order");

        // Order by ID
        var IDSorted =
            from s in students
            orderby s descending
            select s;

        PrintArray(IDSorted, "Students sorted in ID order");
    
        //Console.WriteLine("There are " + students.Count() + " students");

        if (nameSorted.Any())
        {
          //  Console.WriteLine("First in list " + nameSorted.First().ToString());
          //Console.WriteLine("Last in list " + nameSorted.Last().ToString());
        }
    }

    public static void PrintArray<T>(IEnumerable<T> arr, string message)
    {
        Console.WriteLine("{0}", message);

        foreach (T element in arr)
            Console.WriteLine(" {0}", element);

        Console.WriteLine();
    }
}