Creating a Simple Bank Application Using Python

Looking for a simple yet impressive banking application that can help you enhance your Python programming skills or add value to your resume? Check out this excellent bank application written in Python that runs on the command prompt.

This banking application provides various features:

• Users can log in to their existing account and check their debit and credit balances, update the account details
• Additionally, users can open a new account by providing their username, password, email ID, and mobile number
• The admin can view all the details of the registered users

Code Explanation

The code starts with importing the required Python modules and defining a function “clear_screen()” to clear the command prompt screen. Then we create a function “menu()” that displays the menu options and prompts the user to select an option. Once the user selects an option from the menu, the corresponding function is executed.

getpass: This module interacts with the user via the terminal to ask the user for password values without showing what the user types on the screen

os: It provides various functions to interact with the OS like “os.system(‘cls’)” to clear the terminal screen

shelve: shelve module stores and modifies data in a file, keeping it in storage until deletion

shelve.open(): Creates a new file & stores the user's bank details to verify or update the account details

sys.exit(): Allows the user to exit from the program

time.sleep(): This function suspends the execution of the program for a given number of seconds

login() function prompts users to enter their account number, username, and password to log in. The function then verifies the user’s credentials and displays the account details

submenu() function offers users several options such as debit balance, credit balance, show balance, update account details, show account details, and logout. Depending on the user’s selection, the corresponding function is executed

debit_balance() function enables users to debit a specified amount from their account balance. It checks if the user has sufficient balance before updating the account balance

credit_balance() function allows users to credit a specified amount to their account balance

show_balance() function displays the current balance of the logged-in user

update_account() function allows users to update their account details such as username, password, email ID, and mobile number

This program is a great starting point and can be easily tailored to your unique needs by adding additional functionalities.

from getpass import getpass
import os
import shelve
import sys
import time

def clear_screen():
  os.system('cls')
  
def menu():
  clear_screen()
  print("\n1. Login \n2. Signup \n3. Remove Account \n4. Admin \n5. Exit")
  user_input = int(input("\nSelect option: "))
  if user_input == 1:
    login()
  elif user_input == 2:
    signup()
  elif user_input == 3:
    remove_account()
  elif user_input == 4:
    admin()
  elif user_input == 5:
    exit()

def login():
  clear_screen()
  acc_no = input("\nEnter account no: ")
  username = input("\nEnter username: ")
  password = getpass("\nEnter password: ")
  with shelve.open('users.db') as db:
    if acc_no in db:
      if db[acc_no]['Username'] == username:
        if db[acc_no]['Password'] == password:
          print("\n\n",db[acc_no])
          submenu(acc_no)
        else:
          print("\nPassword Incorrect. Please try again")
          time.sleep(2)
          menu()
      else:
        print("\nUsername is incorrect")
        time.sleep(2)
        menu()
    else:
      print("\nNo such account exists")
      time.sleep(2)
      menu()
  db.close()
  
def submenu(acc_no):
  print("\n1. Debit balance \n2. Credit balance \n3. Show balance \n4. Update account details \n5. Show account details \n6. Logout")
  login_input = int(input("\nSelect option: "))
  if login_input == 1:
    debit_balance(acc_no)
  elif login_input == 2:
    credit_balance(acc_no)
  elif login_input == 3:
    show_balance(acc_no)
  elif login_input == 4:
    update_account(acc_no)
  elif login_input == 5:
    print("\n\n",db[acc_no])
  elif login_input == 6:
    menu()
    
def debit_balance(acc_no):
  with shelve.open('users.db', writeback=True) as db:
    print(f"\nCurrent balance: {db[acc_no]['Balance']}")
    debit_balance = int(input("\nEnter debit balance: "))
    if db[acc_no]['Balance']>debit_balance:
      db[acc_no]['Balance'] = db[acc_no]['Balance'] - debit_balance
      print(f"\nBalance successfully updated --> {db[acc_no]['Balance']}")
      time.sleep(2)
    else:
      print("\nOOPS! You have insufficient balance.")
      time.sleep(2)
  db.close()
  clear_screen()
  submenu(acc_no)
      
def credit_balance(acc_no):
  with shelve.open('users.db', writeback=True) as db:
    print(f"\nCurrent balance: {db[acc_no]['Balance']}")
    credit_balance = int(input("\nEnter credit balance: "))
    db[acc_no]['Balance'] = db[acc_no]['Balance'] + credit_balance
    print(f"\nBalance successfully updated --> {db[acc_no]['Balance']}")
  time.sleep(2)
  db.close()
  clear_screen()
  submenu(acc_no)
      
def show_balance(acc_no):
  with shelve.open('users.db') as db:
      print(f"\nCurrent account balance --> {db[acc_no]['Balance']}")
      time.sleep(2)
  db.close()
  clear_screen()
  submenu(acc_no)
  
def update_account(acc_no):
  clear_screen()
  print("\nWhat do you want to update?  \n\n1. Username \n2. Password \n3. Email ID \n4. Mobile No \n5. Back to previous menu")
  update_input = int(input("\nSelect option: "))
  with shelve.open('users.db',writeback=True) as db:
    if update_input == 1:
      username = input("\nEnter username: ")
      db[acc_no]['Username'] = username
      print("\nUsername updated successfully")
    elif update_input == 2:
      password = getpass("\nEnter password: ")
      db[acc_no]['Password'] = password
      print("\nPassword updated successfully")
    elif update_input == 3:
      eid = input("\nEnter email id: ")
      db[acc_no]['Email ID'] = eid
      print("\nEmail ID updated successfully")
    elif update_input == 4:
      mobile_no = input("\nEnter mobile number: ")
      db[acc_no]['Mobile No'] = mobile_no
      print("\nMobile Number updated successfully")
    elif update_input == 5:
      clear_screen()
      submenu(acc_no)
  time.sleep(2)
  db.close()
  clear_screen()
  submenu(acc_no)
  
def signup():
  clear_screen()
  username = input("\nEnter username: ")
  password = getpass("\nEnter password: ")
  eid = input("\nEnter email id: ")
  balance = eval(input("\nEnter initial amount: "))
  mobile_no = input("\nEnter 10 digit mobile number: ")
  if len(mobile_no)==10:
    pass
  else:
    mobile_no = input("\nPlease enter 10 digit mobile number: ")
  with shelve.open('users.db',writeback=True) as db:
    account_no = list(map(int,db.keys()))
    account_no.sort(reverse=True)
    try:
      new_account_no = str(account_no[0]+1)
    except:
      new_account_no = '1001'
    db[new_account_no] = {
    'Username' : username,
    'Password' : password,
    'Email ID' : eid,
    'Balance' : balance,
    'Mobile No' : mobile_no
    }
    db.close()
    print(f"\n{username} added successfully with Account No : {new_account_no} \n\nLogin again with your credentials.")
    time.sleep(2)
    menu()
    
def remove_account():
  clear_screen()
  acc_no = input("\nEnter account number: ")
  with shelve.open('users.db', writeback = True) as db:
    if acc_no in db:
      del db[acc_no]
      print(f"\nAccount removed successfully")
    else:
      print("\nNo such account exists!!")
  db.close()
  time.sleep(2)
  menu()
  
def admin():
  clear_screen()
  with shelve.open('users.db') as db:
    for key, value in db.items():
      print()
      print(f"{key}\n")
      for k,v in value.items():
        print(f"{k} : {v}")
  db.close()
  print("\n\n1. Update details \n2. Back to main menu")
  a_input = int(input("\nSelect option: "))
  if a_input == 1:
    admin_input()
  elif a_input == 2:
    menu()
  
def admin_input():
  clear_screen()
  print("\n\n1. Update account \n2. Remove Account \n3. Back to admin page")
  admin_input = int(input("\nSelect any option: "))
  if admin_input == 1:
    update_account_admin()
  elif admin_input == 2:
    remove_account_admin()
  elif admin_input == 3:
    admin()
    
    
def update_account_admin():
  clear_screen()
  print("\nWhat do you want to update?  \n\n1. Username \n2. Password \n3. Email ID \n4. Mobile No \n5. Balance")
  update_input = int(input("\nSelect option: "))
  with shelve.open('users.db',writeback=True) as db:
    acc_no = input("\nEnter account number: ")
    if update_input == 1:
      username = input("\nEnter username: ")
      db[acc_no]['Username'] = username
      print("\nUsername updated successfully")
    elif update_input == 2:
      password = getpass("\nEnter password: ")
      db[acc_no]['Password'] = password
      print("\nPassword updated successfully")
    elif update_input == 3:
      eid = input("\nEnter email id: ")
      db[acc_no]['Email ID'] = eid
      print("\nEmail ID updated successfully")
    elif update_input == 4:
      mobile_no = input("\nEnter mobile number: ")
      db[acc_no]['Mobile No'] = mobile_no
      print("\nMobile Number updated successfully")
    elif update_input == 5:
      balance = eval(input("\nEnter balance: "))
      db[acc_no]['Balance'] = balance
      print("\nBalance updated successfully")
  db.close()
  admin_input()
  
def remove_account_admin():
  clear_screen()
  acc_no = input("\nEnter account number: ")
  with shelve.open('users.db', writeback = True) as db:
    if acc_no in db:
      del db[acc_no]
      print(f"\nAccount removed successfully")
    else:
      print("\nNo such account exists!!")
  db.close()
  time.sleep(2)
  admin()
  
    
def exit():
  clear_screen()
  sys.exit()
    
clear_screen()
menu()

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