The program design should contain the following:
* The main menu of program is to continue to prompt the user for an arithmetic choice until the user enters a sentinel value to quit the calculator program.
* When the user chooses an arithmetic operation (i.e. addition) the operation is to continue to be performed (i.e. prompting the user for each number, displaying the result, prompting the user to add two more different numbers) until the user enters a sentinel value to end the chosen arithmetic operation.
* If the user chooses division, do not allow the user to divide by 0. Display an error message to user and ask the user to choose another denominator.