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.