Due at the end of lab.

For this lab you will be modifying the simple calculator program that you wrote for Assignment 2. Please review that assignment for the full requirements of that program. You should use your calculator program for this lab.

To complete the lab, make the following modifications to the calculator program:

• In the original version of the program if the user entered an illegal value no operation was performed. Modify your calculator so that any time the user enters an illegal operation an error message is printed and the user is asked for a new value. This will require adding a loop containing a predicate that is based on the user's choice of operation.
• In the initial version of the program it would perform one operation and then exit. Change the program so that when it finishes a calculation it asks the user if they want to perform another calculation. You can have the user enter a 0 for no and 1 for yes, or use a char so they can enter the letter n or y.
• Add an additional operation to the calculator. This operation should calculate the sum of all of the integers between the two numbers the user entered (truncating the numbers if the user entered a real number). For example, if the user entered 5.2 and 8.7 then the calculator should sum all of the values between 5 and 8 (i.e. 5 + 6 + 7 + 8). Remember that if you store a double value in an int variable it is automatically truncated.