Question

Python 3:In this problem, your input file will contain a number of ciphertext and key pairs, separated by a space. You may assume that the ciphertext contains only uppercase letters. However, it is possible that the key may be missing, and your program should handle this case.

The ciphertext has been encrypted by shifting letters in the alphabet by the amount specified by the key. The word HELLO with key = 2 becomes JGNNQ. Letters should wrap around, so PIZZA with key = 1 becomes QJAAB. If the key is missing, your program should output a message "Missing key!".

code.txt

CLGUBA 13

JGNNQ

ZKADQSZ 1

OQJ 4

AKNSR 2

NGBOXKLBMR 7

sample output

Enter the input filename: code.txt
PYTHON
Missing key!
ALBERTA
SUN
CMPUT
UNIVERSITY

Answer 1

Explanation::

• Code in PYTHON is given below
• Please read comments for better understanding of the code
• Code is easy to understand
• Screenshot of the code is also given for the problem of indentation
• Output is given at the end

Code in PYTHON::

"""
Opening file named code.txt in object file
"""
file = open('code.txt')
"""
    Traversing each line in the file
    using for loop
"""
for i in file:
    """Removing newline characters at the end of the line"""
    str=i.rstrip()
    """Converting str into list[]"""
    str=str.split(' ')
    ''' If the length the str array is 1
    then it means that key is not there
    '''
    if len(str)==1:
        print("Missing key!")
    else:
        '''
        We store the key in variable named key
        '''
        key=int(str[1])
        '''
        And we strore the current string in string
        '''
        string=str[0]
        '''
        Below we traverse each character of the string
        and get ASCII value by using ord
        '''
        for i in string:
            val=int((ord(i)+key-65)%26)
            print(chr(val+65),end='')
        print()

Screenshot of the code::

OUTPUT::

Please provide the feedback!!

Thank You!!