C programming exercise

Before starting working on the tutorials and programming assignments you should make sure you are familiar with a few important C programming concepts.

To test your C programming skills you are encouraged to solve the programming exercise described below.

Clone repository

Before you continue, you must clone the module-0-address-book repository.

From the terminal, navigate to a directory where you want the cloned directory to be created and execute the following command.

$ git clone https://github.com/uu-os-2019/module-0-address-book.git


The functions you need to implement are already declared in address_book.h. You should also define the structures you will need in address_book.h. You are free to create more functions if you want.


In the file address_book.c you should implement the functions declared in adress_book.h.


The main() function, which is the entry point of your program will be in a file called main.c.

Representing a person

Create a struct Person that will be used to represent a person. This struct should store:

  • The full name
  • The age
  • The phone number

It is up to you to choose the right datatypes for the fields of the structure.

Representing the address book

Create a struct Address_book that will contain a pointer to an array of struct Person, as well as the size of this array (the number of persons in the address book).

Printing a person

Create a function print_person() that takes a pointer to a Person structure and prints its details on the standard output.

A possible output for a person named John Doe, 42 years old, with the phone number +46712345678:

Name: John Doe
Age: 42
Phone number: +46712345678

Printing an address book

Create a function print_address_book() that takes a pointer to an address book and prints its details on the standard output. Make use of the print_person() function you just created.

A possible output for an address book containing two entries is:

==== Address book (2 entries) =====

Name: John Doe
Age: 42
Phone number: +46712345678

Name: Foo Bar
Age: 24
Phone number: +46787654321

Creating an address book

We will now read information from the user and store it into an address book.

Create a create_address_book() function. This function should:

  • Create (dynamically) an empty address book.
  • Read from the standard input the number of persons that the user intends to put into the address book.
  • Dynamically allocate an array of struct Person of the correct size and store a pointer to it in the address book. You are not allowed to use Variable Length Arrays!
  • In a loop, read from the standard input the information you need for every person to be stored in the address book. Assume that the inputs are correct, so you are not expected to validate them.
  • Return the address book.

Hints: Dynamic allocation is done with malloc(). Reading from the standard input can be done using scanf() or fgets().