A useful technique for catching typing errors is to use a check digit. For example, suppose that a school assigns a six-digit number to each student. A seventh digit can be determined from the other digits with the use of the following formula:

7th digit = (1 * (1st digit) + 2 * (2nd digit)+. . .+6 * (6th digit))%10

When a user types in a student number, the user types all seven digits. If the number is typed incorrectly, the check digit will fail to match in 90% of the cases. Write an interactive program that prompts for a six-digit student number and reports the check digit for that number, using the preceding formula.