public static void Main(string[] args)
{
var salaryCalculator = new SalaryCalculator();//invoker
salaryCalculator.AddSalaryCalculator(new JrSoftwareEngineerSalaryCalculator());
salaryCalculator.CalculateSalary();
salaryCalculator.AddSalaryCalculator(new ProjectManagerSalaryCalculator());
salaryCalculator.CalculateSalary();
}