Write a program that lets the user perform arithmetic operations on two numbers. Your program must be menu driven, allowing the user to select the operation (+, -, *, or /) and input the numbers. Furthermore, your program must consist of following functions:
1. Function showChoice: This function shows the options to the user and explains how to enter data.
2. Function add: This function accepts two number as arguments and returns sum.
3. Function subtract: This function accepts two number as arguments and returns their difference.
4. Function multiply: This function accepts two number as arguments and returns product.
5. Function divide: This function accepts two number as arguments and returns quotient.