Added a Python game and updated README.md

Programs/P80_checking_validation_of_credit_card.py

@@ -0,0 +1,60 @@
+# -*- coding: utf-8 -*-
+"""Checking_validation_of_Credit_card.ipynb
+
+Automatically generated by Colaboratory.
+
+Original file is located at
+    https://colab.research.google.com/drive/1i7AszLLJi-Mrw_iWR10w2F7icdopWFMf
+"""
+
+def validity_check(num):                                                   # this function adds every digit of the card number to a list and,
+    validlist=[]
+    for i in num:
+        validlist.append(int(i))
+    for i in range(0,len(num),2):                                             # applying Luhn Algorithm to check whether resulting sum is divisible by ten
+        validlist[i] = validlist[i] * 2
+        if validlist[i]  >= 10:
+            validlist[i] =  (validlist[i]//10 + validlist[i]%10)
+
+    if sum(validlist)% 10 == 0:
+        print("This is a VALID CARD!")
+
+    else:
+        print('INVALID CARD NUMBER')
+
+def card_number():                                                                     # accepts card number as a string
+
+    n =''
+    while True:
+        try:
+            n = input('Enter your 16 digit credit card number : ')
+
+            if not (len(n) == 16) or not type(int(n) == int) :
+                raise Exception
+
+        except Exception:    
+            print('That is not a valid credit card number. \nMake sure you are entering digits not characters and all the 16 digits.')
+            continue
+
+        else:
+            break
+
+
+    return n
+
+def goagain():
+    return input('Do you want to check again? (Yes/No) : ').lower()[0] == 'y'
+
+def main():
+
+    while True:
+
+        num = card_number()
+        validity_check(num)
+
+
+        if not goagain():
+            break
+
+if __name__ == '__main__':
+    main()

README.md

@@ -46,6 +46,7 @@ Pune, Maharashtra, India.<br />
 2. [Hangman](https://github.com/OmkarPathak/Python-Programs/blob/master/Programs/P37_HangmanGame.py)
 3. [Rock Paper Scissor](https://github.com/OmkarPathak/Python-Programs/blob/master/Programs/P49_RockPaperScissors.py)
 4. [Tic Tac Toe](https://github.com/OmkarPathak/Python-Programs/blob/master/Programs/P75_TicTacToe.py)
+5. Credit card validation checker P80_checking_validation_of_credit_card.py
 
 ## OOP