in php code

Create a class called Employee.

a. The class contains the following properties:

i. Employee ID (text)

ii. Employment starting date (date ddmmyyyy)

iii. StartSalary (Salary obj)

iv. CurrentSalary (Salary obj)

b. The class should contain the following methods:

i. Set and get for each property.

ii. Calculate years of experience.

c. The constructor should allow us to add all the information.

Note: the current salary should be equal to the starting salary.

Note: Salary object contains: Basic Salary, Housing and Transportations. Note: any extra class you may need to create, please create with appropriate methods.