"""
 crypto2.py - 
   - get word from file 'input.txt'
   - change each letter to one higher
   - put word into file 'output.txt

 (I created the file input.txt with the jupyter text editor
  and put the word 'cat' into it.)

    jim@jupyter:~$ ls
    2020-01  backups        crypto.py   input.txt    unix_shell_stuff
    2020-09  circles.ipynb  drawing     output.txt
    2021-02  crypto2.py     drawing.py  __pycache__
    jim@jupyter:~$ cat input.txt
    cat

    jim@jupyter:~$ python crypto2.py
    jim@jupyter:~$ cat output.txt
    dbujim@jupyter:~$

 Notice that in this version, the output file doesn't have
 a newline at the end, which is why it printed as "dbujim...".

 To put a newline in, we could have added output.write("\n")
 after writing the word.

"""

def main():
    input = open("input.txt")                             # input
    data = input.read()       # get whole file
    word = data.strip()       # remove whitespace newlines 
    
    
    new_word = ""                                         # do stuff
    for letter in word:                                   # .
        new_word = new_word + chr(ord(letter) + 1)        # .
        
    output = open("output.txt", "w")  # open for writing - make or replace file
    output.write(new_word)            # put stuff into it

main()