Define a MathOp interface that has four methods for add, subtract, multiply, and divide. These methods only work with integers.
Implementation
You will write a class that implements MathOp to support arithmetic operations. Each method should have two parameters. The divide method will throw an exception if the divisor is 0.
Write a program that uses the interface and implementation to allow the users to perform some arithmetic.
Sample run (text marked as bold are user inputs):

run:
1)add, 2)sub, 3)multiply, 4) divide, 5) exit:1
Enter operands:2 4
6
1)add, 2)sub, 3)multiply, 4) divide, 5) exit:2
Enter operands:4 2
2
1)add, 2)sub, 3)multiply, 4) divide, 5) exit:3
Enter operands:2 3
6
1)add, 2)sub, 3)multiply, 4) divide, 5) exit:4
Enter operands:3 2
1
1)add, 2)sub, 3)multiply, 4) divide, 5) exit:4
Enter operands:2 1
2
1)add, 2)sub, 3)multiply, 4) divide, 5) exit:4
Enter operands:3 0
Division by zero error!
1)add, 2)sub, 3)multiply, 4) divide, 5) exit:5
Bye!