using System;
using System.Linq;

namespace ClassExamples {
   class LinqDemo {
      public static void Main() {
         var students = new [] {
                new {ID = 100, Name = "Tom", Major = "CS"},
                new {ID = 200, Name = "Dave", Major = "CS"},
                new {ID = 300, Name = "Jane", Major = "ECE"}
         };


         // Select example
         var result1 = from s in students
                        select new { s.ID, s.Name };
         foreach (var v in result1) {
            Console.WriteLine(v.ID + "\t" + v.Name);
         }

         // Where example
         var result3 = from s in students
                        where s.Major == "CS"
                        select s;
         Console.WriteLine("CS Students");
         Console.WriteLine("-----------");
         foreach (var v in result3) {
            Console.WriteLine(v.Name);
         }

         // Order by example
         var result4 = from s in students
                        where s.Major == "CS"
                        orderby s.Name ascending
                        select s;
         Console.WriteLine("CS Students");
         Console.WriteLine("-----------");
         foreach (var v in result4) {
            Console.WriteLine(v.Name);
         }

         // Group by example
         var result5 = from s in students
                        group s by s.Major into g
                        select new { Major = g.Key, Count = g.Count() };
         Console.WriteLine("Major Count");
         Console.WriteLine("-----------");
         foreach (var v in result5) {
            Console.WriteLine(v.Major + "\t" + v.Count);
         }

         // Join example
         var result6 = from s1 in students
                        join s2 in students
                        on s1.Major equals s2.Major
                        where s1.ID != s2.ID
                        select new {Name1 = s1.Name, Name2 = s2.Name};
         Console.WriteLine("Major Pairs");
         Console.WriteLine("-----------");
         foreach (var v in result6) {
            Console.WriteLine(v.Name1 + " -- " + v.Name2);
         }
      }
   }
}