using System.Collections.Generic;
public string StudentName
public static void Main()
IList<Student> studentList = new List<Student>()
StudentID = 1, StudentName = "John", Age = 18
StudentID = 2, StudentName = "Steve", Age = 15
StudentID = 3, StudentName = "Bill", Age = 25
StudentID = 4, StudentName = "Ram", Age = 20
StudentID = 5, StudentName = "Ron", Age = 19
bool areAllStudentsTeenAger = studentList.All(s => s.Age > 12 && s.Age < 20);
Console.WriteLine(areAllStudentsTeenAger);
areAllStudentsTeenAger = studentList.Any(s => s.Age > 12 && s.Age < 20);
Console.WriteLine(areAllStudentsTeenAger);
areAllStudentsTeenAger = studentList.Contains(new Student(){StudentID = 3, StudentName = "Bill", Age = 25});
Console.WriteLine(areAllStudentsTeenAger);
areAllStudentsTeenAger = studentList.Contains(new Student(){StudentID = 3, StudentName = "Bill"}, new StudentComparer());
Console.WriteLine(areAllStudentsTeenAger);
class StudentComparer: IEqualityComparer<Student>{
public bool Equals(Student x, Student y){
return x.StudentID == y.StudentID && x.StudentName.Equals(y.StudentName, StringComparison.OrdinalIgnoreCase);
public int GetHashCode(Student obj){
return obj.GetHashCode();