Hi,

two ways you can call Default cunstructor without need of explicit constructor, see the code,

Method 1:

List<Customer> customers = new List<Customer>()
                                           {
                                               new Customer()
                                               {
                                                   AGE = 1,
                               NAME = "gaurav",
                               AMOUNT = 27567.90
                                               },
                                               new Customer()
                                               {AGE = 2,
                               NAME = "manav",
                               AMOUNT = 28533.90},
                                               new Customer()
                                               {AGE = 3,
                               NAME = "anuj",
                               AMOUNT = 29500.90
                                               }
                                           };

Method 2:

var cust1 = new Customer()
                           {
                               AGE = 1,
                               NAME = "gaurav",
                               AMOUNT = 27567.90
                           };
            var cust2 = new Customer()
            {
                AGE = 1,
                NAME = "gaurav",
                AMOUNT = 27567.90
            };
            var cust3 = new Customer()
            {
                AGE = 1,
                NAME = "gaurav",
                AMOUNT = 27567.90
            };

public class Customer
    {
        private int _id;
        private string _name;
        private int _age;
        private double _amt;

        //public Customer(int Id, string Name, int Age, double Amt)
        //{
        //    Id = _id;
        //    Name = _name;
        //    Age = _age;
        //    Amt = _amt;
        //}

        //public Customer()
        //{
        //}

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

        public string NAME
        {
            get { return _name; }
            set { _name = value; }
        }

        public int AGE
        {
            get { return _age; }
            set
            {
                if (_age > 100)
                {
                    // show msgs
                }
                else
                {
                    _age = value;
                }
            }
        }

        public double AMOUNT
        {
            get { return _amt; }
            set { _amt = value; }
        }

        public static void Do_Work(IEnumerable<Customer> pCustomers)
        {
            int iCounter = 0;
            foreach (var pCustomer in pCustomers)
            {
                iCounter++;
                Console.WriteLine(string.Format("Customer {0} : Name : {1}, Age : {2}, Amount : {3}", iCounter.ToString(), pCustomer.NAME, pCustomer.AGE.ToString(), pCustomer.AMOUNT.ToString()));
                Console.ReadLine();
            }
        }

Hope this will help you