Class and Object

  

PYTHON

       Class and Object

       Fill in the blanks

 

       1.Class is Collections of Object.

       2.Object is Collections of data.

       3.Creating an object is called Constructor

       4.Deleting an object is called destructor

       5.Write a different kinds of attribute 2 (data attribute,class attribute)

       6.Private data can be accessed by public member function

       7.private data can be declared with __(underscore)

       8.__init__ means  Constructor

       9.__del__ means destructor

       10.write a syntax of object objectvariable=classname()

 

Answer the following Question

                                                          (4 marks)

          1.Write a program for Class and Object

class Test:

     # A sample method

     def fun(self):

     print("Hello world")

# creating object to a class test

obj=Test()

#Executing the class method

obj.fun()

        2.Write a program for Constructor and Destructor

class sample:

         def __init__(self,x,y):

                     self.x=x

                     self.y=y

         def __del__(self):

                print("An object removed from memory")

         def disp_data(self):

                print("x value-{},y value-{}".format(self.x,self.y))

 

s1=sample(2,4)

s2=sample(4,5)

s3=sample(10,12)

s1.disp_data()

s2.disp_data()

s3.disp_data()

#del command remove one reference and invoke destructor method _ del _ () automatically

del s1

del s2

del s3

        3.Write a program for Constructor Overloading

class jknum:

   def __init__(self,x=1,y=0):

         self.cx=x

         self.cy=y

   def callme(self):

                 print("x value=%d, y value=%d"%(self.cx,self.cy))

b1=jknum(10)

b2=jknum(20,30)

b1.callme()

b2.callme()

        4.Write a program for Class Attribute

class classattrib:

   num=10

   def count_fun(self):

           self.__class__.num+=1

N1=classattrib()

N2=classattrib()

print("\n num value...",N1.num)

print("\n num value...",N2.num)

print("\n num value...",N1.__class__.num)

print("\n num value...",N2.__class__.num)

print("\n num value...", classattrib.num)

N1.count_fun()

N2.count_fun()

print("\n num value...",N1.num)

print("\n num value..",N2.num)

print("\n num value...",N1.__class__.num)

print("\n num value...",N2.__class__.num)

print("\n num value...",classattrib.num)

 

        5.Write a program for Private method and Private Variable

class number: 

    _a=0

_b=0

c=0

def _callme(self,x,y):

                 self._a=x

                 self._a=y

def cal(self):

               s=self._a+self._b+self.c

                return(s)

def maincall(self,x,y):

                 self._callme(x,y)

obj=number()

obj.c=40

obj.maincall(10,20)

print("sum value = %d " %obj.cal())

        6.Write a program for data hiding and Object printing

class MyClass:

        #Hidden member of My Class

         _Hidvar = 0

        #A member method that changes

        #_Hidvar

         def add(self,N):

               self._Hidvar =self._Hidvar + N

               print(self._Hidvar)

#Driver code

myObject = MyClass()

myObject.add(2)

myObject.add(5)

print(myObject._Hidvar)

 

Answer the following Question

                                                          (10 marks)

        1.Write a program for ATM Machine Operation using Class and Object.

v Deposit

v Withdraw

v Balance

v Exit

 class BankAccount:    

    balance = 0

    def withdraw(self,amount):

         self.balance-=amount

         return self.balance

 

    def deposit(self,amount):

         self.balance += amount

         return self.balance

 

    def balanceCheck(self):

         print("\n New balance is...Rs.{}".format(self.balance))

    def bal_return(self):

         return(self.balance)

BT=BankAccount()

while True:

    print("1. Deposit\n")

    print("2. Withdraw\n")

    print("3. Balance\n")

    print("4. Exit")

    ch = int(input("Enter your choice..."))

    if ch == 1:

        while True:

          amt=int(input("Enter amount to Deposit..."))

          if amt>0:

            BT.deposit(amt)

            break

          else:

            print("Enter Valid mount")

            continue

    if ch == 2:

        while True:

           amt=int(input("Enter amount to withdraw..."))

           if BT.bal_return()>amt:

               BT.withdraw(amt)

               break

           else:

             BT.balanceCheck()

             print("\n Low balance.please Enter Less Amount..")

             continue

    if ch ==3:

            BT.balanceCheck()

    if ch ==4:

            break