11. Employee Salary Composition

See: https://www.geeksforgeeks.org/inheritance-and-composition-in-python/

See: https://medium.com/swlh/the-best-way-to-understand-composition-in-python-5-case-studies-and-solution-4b23a6a2cc38

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11.1. Composition

Composition models a has-a-relationship.

Use composition to create components that can be reused by multiple classes.

A composite class can be assigned to an instance variable.

In the code below, self.salary = Salary(monthly_income=monthly_income, bonus_rate=bonus_rate), the composite class, Salary, is assigned to an instance variable, self.salary.

The Salary method, get_total_salary(), can be called from the instance variable: self.salary.get_total_salary().

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11.2. Employee Salary

Tasks

1. Write a Salary class to be assigned to a variable in the Employee class using the scaffold below.

   class Employee:
       def __init__(self, firstname, lastname, monthly_income, bonus_rate):
           self.firstname = firstname
           self.lastname = lastname
           self.salary =         (monthly_income=              , bonus_rate=         )
   
       def get_employee(self):
           print(f"Name: {self.firstname + self.lastname}.")
           print(f"Salary: ${self.salary.get_total_salary()}")
   
   
   class Salary:
       def __init__(self,            ,                 ):
           self.monthly_income = monthly_income
           self.bonus_rate = bonus_rate
   
       def get_annual_salary(self):
           return self.monthly_income * 12
   
       def get_bonus(self):
           return self.monthly_income * self.bonus_rate / 100
   
       def get_total_salary(self):
           return f'{self.                  () + self.get_bonus():.2f}'
   
   
   emp1 = Employee(firstname="Tim", lastname="Lang", monthly_income=8000, bonus_rate=5)
   emp1.get_employee()
   

Q1

Write a Salary class to be assigned to a variable in the Employee class using the scaffold below.

class Employee:
    def __init__(self, firstname, lastname, monthly_income, bonus_rate):
        self.firstname = firstname
        self.lastname = lastname
        self.salary = Salary(monthly_income=monthly_income, bonus_rate=bonus_rate)

    def get_employee(self):
        print(f"Name: {self.firstname + self.lastname}.")
        print(f"Salary: ${self.salary.get_total_salary()}")


class Salary:
    def __init__(self, monthly_income, bonus_rate):
        self.monthly_income = monthly_income
        self.bonus_rate = bonus_rate

    def get_annual_salary(self):
        return self.monthly_income * 12

    def get_bonus(self):
        return self.monthly_income * self.bonus_rate / 100

    def get_total_salary(self):
        return f'{self.get_annual_salary() + self.get_bonus():.2f}'


emp1 = Employee(firstname="Tim", lastname="Lang", monthly_income=8000, bonus_rate=5)
emp1.get_employee()