using System;

using System.Linq;

using System.Collections;

using System.Collections.Generic;

public class Program

{

/*delegate must be globally scoped.*/

//delegate bool IsTeenager(Student s, int maxAge);  

​

    public static void Main()

    {

    /*The collection to query:*/

    IList<Student> studentList = new List<Student>(){

    new Student(){id = 1, name = "John", age = 13},

    new Student(){id = 2, name = "Moin", age = 21},

    new Student(){id = 3, name = "Bill", age = 18},

    new Student(){id = 4, name = "Ram", age = 20},

    new Student(){id = 5, name = "Ron", age = 15},

    };

​

    Console.WriteLine("Avg.");

    var avgAge = studentList.Average(s=> s.age);

        Console.WriteLine(avgAge);

    }

    public class Student

    {

    private int _studentID;

    private string _studentName;

    private int _studentAge;

        public int id{

            get{

            return _studentID;}

            set{

            _studentID = value;

            }

        }

        public string name{

            get{

            return _studentName;

            }

            set{

            _studentName = value;

            }

        }

        public int age{

            get{

            return _studentAge;

            }

            set{

            _studentAge = value;

            }

        }

    }

​

}

​

​