static void Main() { int x = 0; int y = -2; // absoulte // IsPostive if (x.IsPositive()) { Console.WriteLine("X is +ve"); } Console.WriteLine($"Y={y.ABS()}"); List <User> users = new List <User>() { new User() { FirstName = "abc", LastName = "xyz", UserName = "******", Password = "******" }, new User() { FirstName = "rai", LastName = "singh", UserName = "******", Password = "******" }, new User() { FirstName = "urvi", LastName = "verma", UserName = "******", Password = "******" } }; var user = users.Where(x => x.UserName == "temp" && x.Password == "123").FirstOrDefault().GetUserWithoutPassword(); //user.Password = null; Console.WriteLine($"User Detail : {user.FirstName} {user.LastName}, UserName {user.UserName}, Password {user.Password}"); var userswithoutpassword = users.GetUsersWithoutPassword(); foreach (var user1 in userswithoutpassword) { Console.WriteLine($"User Detail : {user1.FirstName} {user1.LastName}, UserName {user1.UserName}, Password {user1.Password}"); } // Dept Table DNo , DName, Loc // Employee , EmpNo, EName, Job, Hiredate, Employee Manager, int MgrId, Salary, Comm, Dept Department, int Dno // select all employee of department id 10 // select all employee who get sal >=5000 // 10 years eperience // select emp who is work under empno no 101 // department wise total salary // get employee of highest // list employee sal + comm = totalsal // // }