in C programming add additional functionality to your phonebook program from lab# 6. Make it possible for users to: 1) Alphabetically sort the list of entries by name (first or last). 2) Find a phone number for a given name. 3) Randomly select a friend from the phonebook for you to call. 4) Delete everyone from the phonebook at the same time

Here is a copy of the code I already wrote to add, delete, and display contacts

#include

#include

#include

// create a struct

struct phonebook{

char fname[20];

char lname[20];

char phone[8];

};

void addfriend(struct phonebook **, int *);

void deletefriend(struct phonebook **, int);

void showPhonebook(struct phonebook **);

int main()

{

int i;

// create an array of type struct phonebook

struct phonebook **arr = (struct phonebook **)malloc(50 * sizeof(struct phonebook *));

// index at which new entry is to be added

int index = 0;

// set all entries of arr to NULL

for( i = 0 ; i < 50 ; i++ )

arr[i] = NULL;

while(1)

{

printf("Enter one of the following options ... ");

printf("1) Add friend 2) Delete friend 3) Show phone book 4) Quit ");

int option;

scanf("%d",&option);

switch(option)

{

case 1 : addfriend(arr, &index);

break;

case 2 : deletefriend(arr, index);

break;

case 3 : showPhonebook(arr);

break;

default : exit(0);

}

}

return 0;

}

void addfriend(struct phonebook **arr, int *index)

{

struct phonebook *temp = (struct phonebook *)malloc(sizeof(struct phonebook));

printf("Enter the name of friend ");

scanf("%s%s", temp->fname, temp->lname);

printf("Enter the phone number ");

scanf("%s", temp->phone);

arr[*index] = temp;

(*index)++;

}

void deletefriend(struct phonebook **arr, int index)

{

char f[20], l[20];

printf("Enter the name of friend ");

scanf("%s%s", f, l);

int i;

// find the required contact

for( i = 0 ; i < 50 ; i++ )

// if contact is found

if(arr[i] && !strcmp(arr[i]->fname, f) && !strcmp(arr[i]->lname, l))

// set that element to NULL

arr[i] = NULL;

}

void showPhonebook(struct phonebook **arr)

{

int i;

for( i = 0 ; i < 50 ; i++ )

// if element is not NULL

if(arr[i])

printf("Name : %s %s Phone Number : %s ",arr[i]->fname, arr[i]->lname, arr[i]->phone);

}