I need to write a program in c that will substitute non-alphanumeric and non-punctuation encryption characters for vowels.
It needs to prompt the user to type in a sequence of 10 encryption characters to be used, a different one for each upper and lower case vowel (aeiouAEIOU). Assignment to a vowel is by the order they are typed. Display a user prompt to type a one-line message, ending with the Return or Enter key.
As the message is typed and encrypted, write the encrypted message to a data file. Then, read the encrypted data file and display it on the next line. Then, read the encrypted data file and write the decrypted message to a different (from the previous) decrypted data file.
Finally, read the decrypted data file and display it on a new line just below the encrypted line.