Write a C++ program for encrypting and decrypting files. Since this program performs two different functionalities (encryption and decryption), prompt the user to select the type of cryptographic technique as shown below:

Welcome to the Cryptographic Techniques Program

Please enter your selection:
1. Encrypt
2. Decrypt

When the user selects 1 or 2, s/he will be asked to specify the input and output files.

This program will be tested using a .txt file.

If the user selects to encrypt the file (i.e. option 1), then the program will encrypt the original text and outputs the encrypted text to a new file.

If the user selects to decrypt the file (i.e. option 2), then the program will decrypt the encrypted text and outputs the decrypted text to a new file.

The program should give the user the option whether to continue with encrypting/decrypting files (i.e. entering letter 'C') or exit the program (i.e. entering the letter 'E').

This program MUST be written using functions and arrays.

The program MUST and can ONLY contain the following function definitions and layout:

/**************************************************************
* This function displays the menu options as in the handout *
**************************************************************/
void displayMenu()
{ /* function body */ }

/**************************************************************
* This function encrypts the content of infile and saves the *
* encrypted text into outfile *
* @param infile string (file that has raw text) *
* @param outfile string (file that will have encrypted text) *
**************************************************************/
void encrypt(string infile, string outfile)
{ /* function body */ }

/**************************************************************
* This function decrypts the content of infile and saves the *
* decrypted text into outfile *
* @param infile string (file that has encrypted text) *
* @param outfile string (file that will have decrypted text) *
**************************************************************/
void decrypt(string infile, string outfile)
{ /* function body */ }

/**************************************************************
* This function takes an character and a cipher key to return *
* an encrypted character. *
* @param c is a char (the character to be encrypted) *
* @param key is an integer (cipher key given in the handout) *
**************************************************************/
char ceaserCipher(char c, int key)
{ /* function body */ }

/**************************************************************
* This function takes an encrypted character and a cipher key *
* to return a decrypted character. *
* @param c is a char (the character to be decrypted) *
* @param key is an integer (cipher key given in the handout) *
**************************************************************/
char ceaserDecipher(char c, int key)
{ /* function body */ }

/**************************************************************
* This is the main function of the program. *
* @return a value to terminate the program successfully *
**************************************************************/
int main()
{
displayMenu();
// 1. Get user input (e.g. encrypt/decrypt and filenames)
// 2. Call the appropriate function(s) to process encryption/decryption
// 3. Then, get user input to continue or exit the program
return 0;
}

**Please write clean code. Any code that does not meet the asking requirements will be rated 0 stars.