banking_code.py

# We will build a real life project to understand oop better based on banking system 
class Atm:
    def __init__(self) :
        self.__pin= ""  # hide the data using `__` so that user can't see that data
        self.__balance=0
        self.__menu()

     # we use getter and setter method to access the private data
    def get_pin(self):     
       return self.__pin

    def set_pin(self,new_pin):
       if type(new_pin)==str:
          
          self.__pin=new_pin
          print("print changed")
       else: 
          print("not allowed")      
        

    def __menu(self):  # we can also hide the method also 
        user_input= input(""" 
                         Hello, How would you like to proceed
                          1.Enter 1 to create pin
                          2.Enter 2 to deposit
                          3.Enter 3 to Withdraw
                          4.Enter 4 to check balance
                          5.Enter 5 to exit

                         """)
        if user_input=="1":
         self.create_pin()
        elif user_input=="2":
           self.deposit()
        elif user_input=="3":
           self.withdraw()
        elif user_input=="4":
           self.check_balance() 
        else:
           print("Bye")          
        

    def create_pin(self):
       self.__pin=input("Enter your pin : ")
       print("Pin set sucessfully")

    def deposit(self):
       temp=input("Enter your pin : ")
       if temp==self.__pin:
          amount=int(input("Enter the amount : "))
          self.__balance=self.__balance+amount
          print("Deposit Sucessfully")
       else:
          print("Invalid pin")   

    def withdraw(self):
       temp=input("Enter your pin : ")
       if temp==self.__pin:
          amount=int(input("Enter the amount : "))
          if amount<self.__balance:
             self.__balance=self.__balance-amount
             print("operation sucessfull")
          else:
             print("Insufficient Funds") 
       else:
          print("Invalid Pin : ")  
          
    def check_balance(self):
       temp=input("Enter your pin : ")
       if temp==self.__pin:
          print(self.__balance)
       else:
          print("invalid pin")