Create a phone book program (C++)that stores and manages contact information contact information is name and correspondi

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Create a phone book program
(C++)that stores and manages contact information
contact information is name and corresponding phone number. the
program reads this information for multiple contacts from a data
file "conatcts.txt" and saves them in a suitable data
structure. once the data is stored, it allows the user to display
all contacts, add a single contact, remove a contact, update a
contact, or populate more contacts from a file called
"update.txt"
It offers the following menu options:
D- Display all contacts in alphabetical order(sorted by first
name),
A- add a contact (user enters name and contact from
console),
R-remove a contact (user enters name from console),
C- change contact information(user enters name and new phone
number from console),
U- reads a list of contacts from the "update.txt" file into the
existing database,
Q- quits the applications
Duplicate names are not allowed. If user tries to add a name
already there, then no overriding is done, same for update. The C
change function can be used to change the phone number of an
existing contact.
Explain efficiency of program using Big(O) notation.
updates.txt file
Zippy 916-334-8763
Vera 888-373-1626
Sally 929-838-1111
Betty 733-736-0912
Mai 616-213-8631
Juan 280-276-9172
Theresa 916-837-2612
Amelia 992-827-1222
Iman 919-000-0010
Wanli 212-928-3333
contacts.txt file
Willie 876-563-5624
De'Aaron 675-345-2652
Nigel 675-645-3456
Vince 567-487-3628
Justin 456-345-4764
Bruno 726-872-5426
Kosta 123-453-6745
Skal 234-567-3418
Harry 324-653-6753
Frank 234-456-2789
Zach 454-364-7839
Harry 324-653-6753
Iman 908-767-6352
Garret 523-647-6540
Buddy 453-647-8987