Using Python as the programming language:

Design and implement a class dayType that implements the day of the week in a program. The class dayType should store the day, such as sun for Sunday. The program should be able to perform the following operations on an object of type dayType:

a$.$ Set the day.

b$.$ Print the day.

c$.$ Return the day.

d$.$ Return the next day.

e$.$ Return the previous day.

f$.$ Calculate and return the day by adding certain days to the current day. For example, if the current day is Monday and we add $4$ days, the day to be returned is Friday. Similarly, if today is Tuesday and we add $13$ days, the day to be returned is Monday.