static void Main(string[] args)
        {
            double netSalary;

            EmployeeStruct employee_value = new EmployeeStruct();

            employee_value.Salary = 40000;

            Console.WriteLine("Gross salary before tax - {0}", employee_value.Salary);

            netSalary = CalculationClass.CalculateTax(ref employee_value);

            Console.WriteLine("Gross salary before tax - {0}", employee_value.Salary);
            Console.WriteLine("Net salary after tax - {0}", netSalary);

            Console.ReadLine();
        }
 public static double CalculateTax(ref EmployeeStruct employee)
 {
     employee.Salary = employee.Salary * 0.75;
     return(employee.Salary);
 }