[FIXED] Why does this code print the constructor?

Issue

class CipherTest:
    def __init__(self):
        self.shift = 0
        self.direction = 'r'
        self.text = "Testing"
    
    # Shift to right function
    def shift_to_right(self, text, shift):
        encrypted_text = ""
        for i in range(len(self.text)):
            c = self.text[i]
            # Encrypt upper case
            if (c == ' '):
                encrypted_text += ' '
            elif (c.isupper()):
                encrypted_text += chr((ord(c) + self.shift - 65) % 26 + 65)
                # Encrypt lower case
            else:
                encrypted_text += chr((ord(c) + self.shift - 97) % 26 + 97)
    
        return encrypted_text
    
    # Shift to left function
    def shift_to_left(self, text, shift):
        encrypted_text = ""
        for i in range(len(self.text)):
            c = self.text[i]
            # Encrypt upper case
            if (c == ' '):
                encrypted_text += ' '
            elif (c.isupper()):
                encrypted_text += chr((ord(c) - self.shift - 65) % 26 + 65)
            # Encrypt lower case
            else:
                encrypted_text += chr((ord(c) - self.shift - 97) % 26 + 97)
    
        return encrypted_text
    
if __name__ == "__main__":
    user_text = str(input())
    user_shift = int(input())
    user_direction = str(input().lower())  # user inputs
    Cipher_Message = CipherTest()  # create an instance of the class
    if user_direction == 'l':  # picking left or right 
        print(CipherTest.shift_to_left(Cipher_Message, user_text, user_shift))
    
    if user_direction == 'r':
        print(CipherTest.shift_to_right(Cipher_Message, user_text, user_shift))

Am I calling the functions within my class incorrectly? Currently no matter the input, it prints "Testing". I'm new to classes but I believe that in the last couple lines, I am calling the new instance, telling it which method to perform, then feeding it the variables it needs to successfully run. From there it should be printing the 'encrypted_text' that is returned using my methods.

Solution

The issue is that CipherTest have attributes direction, shift and text but you also have local variables that you pass as parameter which you don't use

So your method keep using Testing and 0, that returns Testing so

---

The easiest, is to remove the attributs, so the class instance can do both direction, and in fact the method can be static (meaning no instance needed, only the class)

class CipherTest:

    @staticmethod
    def shift_to_right(text, shift):
        encrypted_text = ""
        for c in text:
            if c == ' ':
                encrypted_text += ' '
            elif c.isupper():
                encrypted_text += chr((ord(c) + shift - 65) % 26 + 65)
            else:
                encrypted_text += chr((ord(c) + shift - 97) % 26 + 97)
        return encrypted_text

if __name__ == "__main__":
    user_text = "hey how are you"
    user_shift = 2
    user_direction = "l"

    if user_direction == 'l':
        enc = CipherTest.shift_to_left(user_text, user_shift)
        print(enc)  # encrypted
        print(CipherTest.shift_to_right(enc, user_shift))  # back to plain

    elif user_direction == 'r':
        enc = CipherTest.shift_to_right(user_text, user_shift)
        print(enc)  # encrypted
        print(CipherTest.shift_to_left(enc, user_shift))  # back to plain

---

Another example, so you understand better, is to put the shift as class attribut, in order to use ise, we need to save in the class with self.shift = shift then we can use one cipher instance, with it's shift, to do both operation (also see how we really call a instance method)

class CipherTest:

    def __init__(self, shift: int):
        self.shift = shift

    def shift_to_right(self, text):
        encrypted_text = ""
        for c in text:
            if c == ' ':
                encrypted_text += ' '
            elif c.isupper():
                encrypted_text += chr((ord(c) + self.shift - 65) % 26 + 65)
            else:
                encrypted_text += chr((ord(c) + self.shift - 97) % 26 + 97)
        return encrypted_text

if __name__ == "__main__":
    user_text = "hey how are you"
    user_shift = 2
    user_direction = "l"

    cipher = CipherTest(user_shift)

    if user_direction == 'l':
        enc = cipher.shift_to_left(user_text)
        print(enc)  # encrypted
        print(cipher.shift_to_right(enc))  # back to plain

    elif user_direction == 'r':
        enc = cipher.shift_to_right(user_text)
        print(enc)  # encrypted
        print(cipher.shift_to_left(enc))  # back to plain

Answered By - azro

Answer Checked By - Dawn Plyler (PHPFixing Volunteer)