Write a program that defines an interface having the following methods: addition, subtraction, multiplication, and division. Create a class that implements this interface and provides appropriate functionality to carry out the required operations. Hard code two operands in a test class having a main method that calls the implementing class.

Hello, you haven't provided the programing language in which you need the code, I'll explain how to do it using Python, and you can follow the same logic to make a program in the programing language that you need.

Answer:

1. # -*- coding: utf-8 -*-

2. #Python

3. class Calculator:

4. def add(self):

5. print(a + b)

6. def sub(self):

7. print(a - b)

8. def mul(self):

9. print(a * b)

10. def div(self):

11. print(a / b)

12.

13. obj = Calculator()

14. choice = 1

15. while choice != 0:

16. a = int(input("\nEnter first number: "))

17. b = int(input("Enter first number: "))

18.

19. print("\n0. EXIT")

20. print("1. DIVISION")

21. print("2. ADDITION")

22. print("3. SUBTRACTION")

23. print("4. MULTIPLICATION")

24.

25. choice = int(input("\nEnter your choice: "))

26. if choice == 1:

27. obj.div()

28. elif choice == 2:

29. obj.add()

30. elif choice == 3:

31. obj.sub()

32. elif choice == 4:

33. obj.mul()

34. else:

35. break

Explanation:

From lines 1 to 12 we define the object with four methods, addition, subtraction, multiplication, and division. Each method contains the operation between two variables inside a print function
On line 13 we instantiate our class
On line 14 we declare the variable choice that is going to store the operation that the user wants to perform
On line 15 we declare a while loop, this is going to keep running the program until the user wants to exit
From line 16 to 18 we ask the user to enter two numbers
From line 19 to 24 we print the possible operation, assigning a number for each operation, this indicates to the user what number to press for what operation
On line 25 we ask the user for the operation
From lines 26 to 35 we check the user input an accordingly we call the corresponding method to performs the operation