fixed indexing error (OmkarPathak#23)

Enter your message: vishal
Enter you key [1 - 26]: 7
Encrypt or Decrypt? [E/D]: e
---------------------------------------------------------------------------
IndexError                                Traceback (most recent call last)
<ipython-input-9-9d857a810c45> in <module>
     35 
     36 if __name__ == '__main__':
---> 37     main()

<ipython-input-9-9d857a810c45> in main()
     30 
     31     if choice.lower().startswith('e'):
---> 32         print(encrypt(message, key))
     33     else:
     34         print(decrypt(message, key))

<ipython-input-9-9d857a810c45> in encrypt(message, key)
      9             num = LETTERS.find(chars)
     10             num += key
---> 11             encrypted +=  LETTERS[num]
     12 
     13     return encrypted

IndexError: string index out of range

______________________________________________
Above issue was solved

Author: Monsieurvishal

Programs/P40_CipherText.py

@@ -11,7 +11,10 @@ def encrypt(message, key):
         if chars in LETTERS:
             num = LETTERS.find(chars)
             num += key
-            encrypted +=  LETTERS[num]
+            if num>25:
+                num=num%25
+                num=num-1
+            encrypted =encrypted + LETTERS[num]
 
     return encrypted
 
@@ -21,8 +24,11 @@ def decrypt(message, key):
     for chars in message:
         if chars in LETTERS:
             num = LETTERS.find(chars)
-            num -= key
-            decrypted +=  LETTERS[num]
+            if num>25:
+                num=num%25
+                num=num-1
+            num = num -key
+            decrypted =decrypted+LETTERS[num]
 
     return decrypted