LAB2: ISBN and UPC
 In this lab we are going to implement ISBN (International Standard Book Number) and UPC (Universal Product Code) ID's.
An ISBN is a 10-digit number where the first 4 digits determine the publisher, the next 5 digits are publisher's code number for the book. The last digit is a safety check digit. The last digit of an ISBN
x_1x_2x_3x_4x_5x_6x_7x_8x_9x_10
is so chosen that the sum
1*x_1+2*x_2+3*x_3+4*x_4+5*x_5+6*x_6+7*x_7+8*x_8+9*x_9+10*x_10
is divisible by 11 (i.e. an integer multiple of 11).
Sometimes it is necessary to choose x_10 to be 10, in that case an X is used in place of 10.

The last digit of a 12 digit UPC  x_1x_2x_3x_4x_5x_6x_7x_8x_9x_10x_11x_12 is so chosen that the sum

3*x_1+1*x_2+3*x_3+1*x_4+3*x_5+1*x_6+3*x_7+1*x_8+3*x_9+1*x_10+3*x_11+1*x_12
is divisible by 10.

Your program should present a menu to the user and let him/her choose from one of the alternatives:
Calculate an ISBN check digit
Calculate a UPC check digit
Quit the program.

You should use a switch statement to implement the menu.

A typical dialogue looks like this:

This program calculates check digits for ISBN and UPC ID's.
Enter 1 for ISBN
Enter 2 for UPC
Enter 0 to quit
Your choice: 1
Please enter the first 9 digits of the ISBN number (with a space between the digits) whose check digit is to be computed:  0 4 7 1 0 2 3 7 1
The complete ISBN with check digit is 0-471-02371-X
This program calculates check digits for ISBN and UPC ID's.
Enter 1 for ISBN
Enter 2 for UPC
Enter 0 to quit
Your choice: 2
Please enter the first 11 digit of the UPC (with a space between the digits) whose check digit is to be computed: 1 2 3 4 5 6 7 8 9 0 1
The full UPC number with check digit is 1-23456-78901-2
This program calculates check digits for ISBN and UPC ID's.
Enter 1 for ISBN
Enter 2 for UPC
Enter 0 to quit
Your choice: 0
Good Bye!...