Can anyone help me about this question>>>?? (Microsoft Visual C++)

A company wants to transmit data over the telephone, but they are concerned that their phones may be tapped. All of their data is transmitted as four-digit integers. They have asked you to write a program that will encrypt their data so that it may be transmitted more securely. Your program should read a four-digit integer and encrypt it as follows: Replace each digit by the remainder after the sum of that digit plus 7 is divided by 10. Then swap the first digit with the third, and swap the second digit with the fourth. Then print the encrypted integer. (7 marks)

Sample output:

Enter a four-digit number to be encrypted: 5678
Encrypted number is 4523