static void Main(string[] args)
        {
            List <college> l = new List <college>()
            {
                new college()
                {
                    id = 43, studentname = "veeru", lastname = "rallabandi", branch = "MCA"
                },
                new college()
                {
                    id = 51, studentname = "maheshmadhu", lastname = "goteti", branch = "MCA3"
                }
            };

            //create instance of Democomparer
            DemoCompare d = new DemoCompare();

            //using Method syntax

            //It return true bcoz pass two arguments
            var res1 = l.Contains(new college()
            {
                id = 43, studentname = "veeru", lastname = "rallabandi", branch = "MCA"
            }, d);

            Console.WriteLine(res1);
            var stu = new college()
            {
                id = 55, studentname = "ravi", lastname = "kumara", branch = "MPC"
            };

            //using Query syntax
            var res2 = (from i in l select i).Contains(stu, d);

            Console.WriteLine(res2);
        }
        static void Main(string[] args)
        {
            List <int> l = new List <int>()
            {
                32, 22, 34, 36, 71, 25
            };

            //using Method syntax
            var res1 = l.Contains(22);

            Console.WriteLine(res1);

            //Using Query syntax
            var res2 = (from i in l select i).Contains(22);

            Console.WriteLine(res2);

            //
            string[] s = { "veerababu", "madhu", "mahesh", "sampath" };

            //It is belongs to System.Collections.Generic
            bool res3 = s.Contains("madhu");

            Console.WriteLine(res3);

            //It is belongs to System.Linq
            var res5 = s.AsEnumerable().Contains("veerabau");

            Console.WriteLine(res5);

            var res4 = (from i in s select i).Contains("mahesh");

            Console.WriteLine(res4);

            //using custom type

            college c1 = new college()
            {
                id = 12, branch = "MCA", studentname = "veeru", lastname = "rallabandi"
            };

            var res6 = college.getdatails().Contains(c1);

            Console.WriteLine(res6);

            var res7 = (from i in college.getdatails() select i).Contains(c1);

            Console.WriteLine(res7);


            //using Method syntax

            List <college> ll = new List <college>();

            //only checks reference not values
            var res8 = ll.Contains(new college()
            {
                id = 19, branch = "MCA", studentname = "veeru", lastname = "rallabandi"
            });

            Console.WriteLine(res8);
        }