Question $2[70$ points$]$

In this question, you are going to modify the functionality of phonebook.c$.$ Recall that a

link list is a data$-$structure that contains a pointer to the next object. In A$4$ we used an

array, but that has some disadvantages. We are going to modify phonebook.c to use a list

structure. We will still use an array to allocate all the items we need, so will need a method

to keep track of which items are used, and which are not $($this is usually called a free$-$list$),$ as

well as a method to know what item in the array the list starts at $($usually called the head of

the list$).$ It$$s a good practice to put all of the components together into a structure that can

be passed to functions needing to work on the list we will call this struct phonebook list

$($a$)(20$ points$)$ Create a structure that contains all the components needed to manage the

list. Modify the structure of the phonebook entries to include pointer to the next item

in the list. Write a function phonebook init initialize the array of structures, and any

supporting structures you need. This function should take $1$ argument, a pointer to

struct phonebook list.

$($b$)(10$ points$)$ Modify phonebook add from A$4$ to use the list structure. This function

should find a node on the free$-$list and add it to the end off the list. It should take $2$

arguments:

$(1)$ a pointer to struct phonebook list

$(2)$ the struct to add

As before, the function should return an int: $0$ if the item is added successfully, and

$-1$ if the item is not. Note that unlike in A$4,$ the size is no longer a required parameter.

$($c$)(10$ points$)$ Modify phonebook find from A$4$ to work with the list structure. It will

take $2$ arguments.

$2$

$(1)$ a pointer to struct phonebook list

$(2)$ a key $($a name$)$ to find

This function should return a pointer to the first entry that matches the name $($starting

at the head$).$ If no match is found, then the function should return NULL.

$($d$)(10$ points$)$ Modify phonebook remove from A$4$ to work with the list structure. It

should take $2$ arguments:

$(1)$ a pointer to struct phonebook list

$(2)$ a key $($a name$)$ to remove

If the key is found it should be removed from the list $($and the list relinked$),$ and the

node should be added to the free$-$list. The function should return am int: $0$ if the

item was found and removed. $-1$ if the item could not be found.

$($e$)(10$ points$)$ Modify phonebook print from A$4$ to work with the list structure. it should

take $1$ argument.

$(1)$ a pointer to struct phonebook list

The function then prints all the phonebook entries, each on a separate line. The output

should be similar to the following:

"Jon" $->11234567890$

"Kyle" $->13220000001$

$($f$)(10$ points$)$ Modify main from A$4$ to work with the list structure. You will need to call

phonebook init, and modify calles to phonebook add, phonebook find, phonebook remove,

and phonebook print. All other functionality should be the same as A$4($and in$-$fact

it$$s operation should be identical$).$

$$a$$ for add; e$.$g$.,$

a

Jon

$11234567890$

This should add a phonebook entry with the given name and phone number.

$$f$$ for find; e$.$g$.,$

f

Jon

$3$

In this example, the output should be the value corresponding to $$Jon$$ if the key

exists in the phonebook, or $$Key not found$$ if the key is not in the phonebook.

$$r$$ for remove; e$.$g$.,$

r

Jon

The output should be $$success$$ or $$fail$,$ depending on whether the key was found

and removed.

$$p$$ for print all; e$.$g$.,$

p

The output should be all phonebook entries.

$$q$$ to quit the program.