Question 4: Binary File Operations

Write a menu-driven program to add and display records in a binary file which contains at least three product records with the following fields:

• pname (str)
• price (float)
• qty (int)

Solution

# Q4. Write a program to create a binary file 'products.dat' using pickle module.
#     The program should have a menu with options to:
#     1. Add a new product (with product name, price, and quantity)
#     2. Display all products stored in the file
#     3. Exit the program

import pickle


# Function to add a new record
def add_record():
    # 'ab' opens for appending; it creates the file if it doesn't exist
    with open("products.dat", "ab") as f:
        pname = input("Enter Product Name: ")
        price = float(input("Enter Price: "))
        qty = int(input("Enter Quantity: "))
        record = [pname, price, qty]
        pickle.dump(record, f)
        print("Product added successfully!")


# Function to display all records
def display_records():
    print("\n--- Product List ---")
    print('Product Name',",",'Price,',",",'Quantity')
    print("-" * 40)
    try:
        with open("products.dat", "rb") as f:
            while True:
                try:
                    rec = pickle.load(f)
                    print(rec[0],",",rec[1],",",rec[2])
                except EOFError:
                    break
    except FileNotFoundError:
        print("Error: The file does not exist yet. Add a record first!")


# --- Main Menu ---
while True:
    print("\n1. Add Product")
    print("2. Display All Products")
    print("3. Exit")

    choice = input("Enter choice (1-3): ")

    if choice == "1":
        add_record()
    elif choice == "2":
        display_records()
    elif choice == "3":
        print("Exiting...")
        break
    else:
        print("Invalid choice!")

# Q4. Write a program to create a binary file 'products.dat' using pickle module.
#     The program should have a menu with options to:
#     1. Add 3 products at once (with product name, price, and quantity)
#     2. Display all products stored in the file
#     3. Exit the program

import pickle


# Function to add 3 records at once
def add_record():
    # 'ab' opens for appending; it creates the file if it doesn't exist
    with open("products.dat", "ab") as f:
        for i in range(1, 4):
            print(f"\n--- Enter details for Product {i} ---")
            pname = input("Enter Product Name: ")
            price = float(input("Enter Price: "))
            qty = int(input("Enter Quantity: "))
            record = [pname, price, qty]
            pickle.dump(record, f)
            print(f"Product {i} added successfully!")
        print("\nAll 3 products have been added!")


# Function to display all records
def display_records():
    print("\n--- Product List ---")
    print('Product Name',",",'Price,',",",'Quantity')
    print("-" * 40)
    try:
        with open("products.dat", "rb") as f:
            while True:
                try:
                    rec = pickle.load(f)
                    print(rec[0],",",rec[1],",",rec[2])
                except EOFError:
                    break
    except FileNotFoundError:
        print("Error: The file does not exist yet. Add a record first!")


# --- Main Menu ---
while True:
    print("\n1. Add Product")
    print("2. Display All Products")
    print("3. Exit")

    choice = input("Enter choice (1-3): ")

    if choice == "1":
        add_record()
    elif choice == "2":
        display_records()
    elif choice == "3":
        print("Exiting...")
        break
    else:
        print("Invalid choice!")

import pickle

def add_record():
    pname = input("Product Name: ")
    price = float(input("Price: "))
    qty = int(input("Quantity: "))
    rec = [pname, price, qty]
    with open("products.dat", "ab+") as fh:
        pickle.dump(rec, fh)

def display():
    print("Start >----------")
    with open("products.dat", "rb+") as fh:
        try:
            while True:
                data = pickle.load(fh)
                print(data)
        except Exception:
            print("End   >----------")

def menu():
    while True:
        print("1.add_record | 2.Display | 3.Exit")
        ch = int(input("Enter your choice: "))
        if ch == 1:
            add_record()
        elif ch == 2:
            display()
        elif ch == 3:
            break
        else:
            print("Somthing went wromg")

menu()