has asked you to write a program that will encrypt it so that it may be transmitted more
securely. All the data is transmitted as four-digit integers. Your application should read a
four-digit integer entered by the user and encrypt it as follows: Replace each digit with
the result of adding 7 to the digit and getting the remainder after dividing the new value
by 10. Then swap the first digit with the third, and swap the second digit with the fourth.
Then print the encrypted integer. Write a separate application that inputs an encrypted
four-digit integer and decrypts it (by reversing the encryption scheme) to form the
original number. [Optional reading project: Research "public key cryptography" in general
Fig: 1