Chapter $13$ Lab $-$ Encrypting and Decrypting Files$($C$++)$

Prog $1.$ File Encryption: File encryption is the science of writing the contents of a file in a secret code.

Your encryption program should work like a filter reading the contents of one file, modifying each

character in the input file into a code, and then writing the coded characters out to a second file. The

second file will be a version of the first file but written in a secret code.

In Notepad or something similar, you will create a file with text in it$.$ It should be several lines long.

Your program should read the file character by character and make some change to the character

before writing that character to a second new encrypted file. See program $13-8$ to see how to read

and write one character at a time.

You may come up with an encryption technique of your own or use something simple like adding $10$ to

the ASCII code of each character in the file before it is written to the second file.

Prog. $2-$ File Decryption: Write a program that decrypts the file produced by the program in Prog. $1.$

The decryption program should read the contents of the coded file, restore the information to its

original state and write it to another $($third$)$ file. Example: If you added $10$ to each character in the first

program, subtract $10$ from each character in this program. $($The output file of program $2$ should be the

same as the input file of program $1)$

Error Checking: Your program should check the fail bit after each open, read, and write operations.

Display an error message if the operation failed. Test your program to make sure that each of these

tests works correctly. $($Example$,$ use invalid file name to get a file open error$).$

You should have two programs to turn in $($They should be nearly identical except one encrypts and one

decrypts$).$