Student marks grading

Author: imDarshanGK

Caesar_cipher.py

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+alphabet = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z']
+def encryption(plain_text,shift_key):
+    cipher_text = ""
+    for char in plain_text:
+        if char in alphabet:
+            position = alphabet.index(char)
+            new_position = (position+shift_key)%26
+            cipher_text += alphabet[new_position]
+        else:
+            cipher_text += char
+    print(f"Here's is the text after encryption: {cipher_text}")
+
+def decryption(cipher_text,shift_key):
+    plain_text = ""
+    for char in cipher_text:
+        if char in alphabet:
+            position = alphabet.index(char)
+            new_position = (position-shift_key)%26
+            plain_text += alphabet[new_position]
+        else:
+            plain_text += char
+    print(f"Here's is the text after decryption: {plain_text}")
+
+end_program = False
+while not end_program:        
+    what_to_do = input("Type 'encrypt' for encryption, type 'decrypt' for decryption:\n")
+    text = input("Type your message:\n").lower()
+    shift = int(input("Enter shift key:\n"))
+    if what_to_do=="encrypt":
+        encryption(plain_text=text, shift_key=shift)
+    elif what_to_do=="decrypt":
+        decryption(cipher_text=text, shift_key=shift)
+    play_again = input("Type 'yes' to continue, type 'no' to exit.\n")
+    if play_again == 'no':
+        end_program = True
+        print("Have a nice day! Bye..")

README.md

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+# Caesar Cipher Python
+Encryption and Decryption