Question

A global bank manages its customer in a binary data file “Bank.DAT” with the following fields:
• Account number
• Account holder’s name
• Account balance
Give function definitions to do the following:
a) Write a function to accept the data fields from the user and write to file “Bank.DAT”.
b) Write a function to modify account holder details according to their account number and display the updation.

Answer 1

Language:

Python

Program:

a)

def createFile():

   import pickle

   f=open('Bank.dat','wb')

   record=[]

   while True:

       accno=input("Enter account number:")

       holder=input(f"Enter {accno} holder's name: ")

       balance=float(input(f"Enter {accno}'s balance: "))

       choice=input("Wanna enter more (Y/N)?: ")

       record.append([accno, holder, balance])

       if choice=='N':

           break

   pickle.dump(record,f)

   print(len(record),'record(s) inserted')

   f.close()

b)

def update():

   import pickle

   f=open('Bank.dat','rb+')

   read=pickle.load(f)

   found=0

   acc=input('Enter account number to update: ')

   for i in read:

       if i[0]==acc:

           print("Make the following choice for updation: \nHolder's name\t1 \nAccount Balance\t2 \nCancel updation\t3")

           choice=int(input("Enter your choice: "))

           found+=1

           if choice==1:

               i[1]=input('Enter new Holder\'s name: ')  

               break

           elif choice==2:

               i[2]=int(input("Enter new Balance:"))

               break

           elif choice==3:

               print("Aborting updation.")

           else:

               print("Invalid choice")  

               break        

       else:

           found+=0

   if found==1:

       f.seek(0)

       pickle.dump(read,f)

       print("Done.")  

   else:

       print("Record not found.")      

   f.close()

Explanation:

• def defines function and accepts input though while loop and loads them into the binary file after creating it using pickle module.
• In the second function option is provided to update the data and update is though rb+ mode with seek, dump function if the file had that specific record.