Question

I am confuse between the best way to organize dependency between multiple classes
assume i have the following classes
Employee,
Salary,
DataAccess

Should i go for:
Option1

Employee emp = new Employee();
Salary sal = new Salary();
DataAccess data = new DataAccess();

sal.Calculate(emp);
data.Save(emp);

or Option2

Employee emp = new Employee();
Salary sal = new Salary();

sal.Calculate(emp); //once salary has been calculated salary object will initialize  data access class to do the actual saving.

or Option 3

Employee emp = new Employee();
emp.Calculate(); // employee object will encapsulate both the salary and data access object

Answer 1

Usually Employee HAS-A salary. So I’d go with something like:

Employee emp = new Employee();
emp.Salary = new Salary();

You can create a generic class that would fetch all of the salary calculation business rules in it(from a data source), and calculate salary for employees based upon employee attributes.

SalaryCalculator.CalculateSalary(emp); //I'd agree with Silky
DataAccess.Save(emp); //This shall save changes in emp as well as in salary.

–EDIT–

This is in response to your comment.

Your hrms object(if any) should then encapsulate the Employee, and provide a CalculateSalary option.

How about something like:

yourHrms.Employees.Add(new Employee(Age, Name, DateOfBirth, EmployedSince, TotalExperience, IsManager, new Salary(someStartPointForSalaryIfAny));

Here your Salary class would inherit from your abstact BaseSalary class, that would contain the business rules, and would perform the Calculate()ions. Therefore, the new Salary(someStartPointForSalaryIfAny) would perform the calculation internally.

To save your object you can have:

yourHrms.Employees.Save();//Saves all employees.
yourHrms.Employees[0].Save();//Save this.