25.Write a menu-driven Python program to create a Phone Book using a dictionary. Key = Person Name Value = Mobile Number The program should: Add Contact Search Contact Update Contact Delete Contact Display All Contacts

# Menu-driven program to create a Phone Book using a dictionary

phone_book = {}

while True:
    print("\n========== PHONE BOOK MENU ==========")
    print("1. Add Contact")
    print("2. Search Contact")
    print("3. Update Contact")
    print("4. Delete Contact")
    print("5. Display All Contacts")
    print("6. Exit")
    print("=====================================")

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

    if choice == 1:
        # Add Contact
        name = input("Enter person's name: ")
        mobile = input("Enter mobile number: ")

        phone_book[name] = mobile
        print("Contact added successfully.")

    elif choice == 2:
        # Search Contact
        name = input("Enter person's name to search: ")

        if name in phone_book:
            print("Mobile Number:", phone_book[name])
        else:
            print("Contact not found.")

    elif choice == 3:
        # Update Contact
        name = input("Enter person's name to update: ")

        if name in phone_book:
            mobile = input("Enter new mobile number: ")
            phone_book[name] = mobile
            print("Contact updated successfully.")
        else:
            print("Contact not found.")

    elif choice == 4:
        # Delete Contact
        name = input("Enter person's name to delete: ")

        if name in phone_book:
            del phone_book[name]
            print("Contact deleted successfully.")
        else:
            print("Contact not found.")

    elif choice == 5:
        # Display All Contacts
        if len(phone_book) == 0:
            print("Phone book is empty.")
        else:
            print("\n========== ALL CONTACTS ==========")

            for name, mobile in phone_book.items():
                print("Name:", name)
                print("Mobile Number:", mobile)
                print("-------------------------------")

    elif choice == 6:
        # Exit
        print("Program terminated.")
        break

    else:
        print("Invalid choice. Please try again.")