C++ Nothing too advanced please

For example, usually the frequency of letter "e" is 12%. If one calculates the frequencies of each letter and finds that a certain letter has 12% frequency, then it is most probably a replacement of letter "e". In this case the value for k can easily be guessed and the cypher can be broken. You are going to apply that technique to an integer number of 5 digits. Create a .cpp file named encrypt.cpp. In this program, ask the user to enter a value for k. Then ask the user to enter a 5- digit integer. Encrypt the number using the digit alphabet 0123456789" and store it in another integer variable. Print the value of the encrypted integer. For example: If k is 3, then the number 25764 is encrypted as 58097. When you add 3 to each digit if it passes the value 9, apply a modulus 10 operation on it. Think of a similar solution when you decrypt. Then, create another file decrypt.cpp. Assume that k is already known. Ask the user to enter the k value and then a 5-digit integer. Then decrypt the value to the original. Sample output for encrypt.cpp Enter key value k: 3 Enter a 5-digit integer to encrypt: Encrypted value: 58097 25764