I have attempted this on my own and am struggling quite a lot at this point. I need to finish the code by adding the three functions below:

struct node * insert(struct node * start, int dataAfter, int newData);

struct node * find(struct node * start, int data);

int delete(struct node * start, int data);

I believe i am correct in assuming that the only time i'd need to use the insert function is when i have the "i" followed by two separate numbers. I will need to insert the second number after the first which could possibly be (beginning, middle, or end). Please be as detailed and make it easy to understand what each important line of code is doing as I am just not understanding this linked list concept in code form and am a beginner in using single linked lists. And if possible, please include sample output. Thank you so much sir/ma'am.

/*

* Lab 1

* The objective of this lab is to add the following

* functionality to the code shown below.

* 1) Insert a node after a specific data element in the

* list. (This was implicit in the lecture this after-

* noon. It is now explicit.)

* 2) Remove a node from the list.

*

* Note that both the insert and the removal (deletion)

* would require that a node has been specified or

* selected for insertion or removal.

* Therefore the following functions would be needed.

* A) Find, where the node's data would match the input

* data.

* B) There is an implication that the input file would

* be able to accept an insert, find, and delete command

* a specific node based on the input data value.

* C) The input file specification should therefore be

* modified to support the following input data format.

*

* Input data format:

** command value

** where a command is identified as follows:

** - i integerValue // i is the insert command

** // where the node is inserted

** // in a new node AFTER having

** // "found" the node specified

** // in the preceding "find"

** - f integerValue // f is the find command

** - d integerValue // d is the delete command

** - p // p is the printAll command

*

* The function prototypes are:

-> struct node * insert(struct node * start, int dataAfter, int newData);

*** returns the inserted node's address is successful

*** NULL address if it fails.

**** inserts newData in the created slot following first dataAfter

**** if no dataAfter exists, add to the bottom of the list

-> struct node * find(struct node * start, int data)

*** returns the found node's address is successful

*** NULL address if it fails to find the node.

-> int delete(struct node * start, int data);

*** returns 0 if successful

*** 1 if it fails.

* See the sample input statements at the end of the source file.

*/

#include

#include

typedef struct node {

int data;

struct node *next;

} node;

struct node * addToList(struct node *base, int data)

{

struct node *newNode = NULL;

struct node *temp = base; //FJ

if (base == NULL)

{

base = malloc( sizeof(struct node));

// malloc defend

base->data = data;

base->next = NULL;

return base;

}

//Find the bottom of the list starting from the base

while (temp->next != NULL) //FJ was base NOT temp

{

temp = temp->next; //FJ was base NOT temp

}

//Now at the end of the list

newNode = malloc( sizeof(struct node)); //get memory for new node

//Defend against bad malloc

temp->next = newNode; // add the new node to bottom of the list (FJ update)

newNode->data = data; // slap the data into the list

newNode->next = NULL; // terminate the list by setting next to NULL

return base; //return the new end of the list to the caller

//Shouldnt we return newNode?

}

/*

* Walk the list and print the data

*/

void printList(struct node *list)

{

while (list != NULL)

{

fprintf(stdout, "data: %3d ", list->data);

list = list->next;

}

return;

}

/*

* pass the input file to main, then add the data from the input file

* to the list. NB The list starts as an empty list.

*/

int main(int argc, char **argv)

{

struct node *root = NULL; // The root of the list

struct node *temp = NULL;

// struct node *base = NULL; // Placeholder for current end of the list

char *inBuf = NULL; // input buffer

int data = 0;

FILE * ifp;

inBuf = malloc(100); //get a 100 character buffer for input data

if (NULL == inBuf) // Check for success

{ //Let 'em know we failed to get a buffer

fprintf(stderr, "No memory - good bye! ");

return -1;

}

ifp = fopen(argv[1], "rwb"); //Get the filename from the command line

if (NULL == ifp) // Check for success

{ //Let 'em know the filename wasn't found

fprintf(stderr, "%s file not found. ", argv[1]);

return -1;

}

/*

* Read the file, then add the data to the list

* All the while keep track of the last added node in temp

*/

while (fscanf(ifp, "%s", inBuf) != EOF)

{

fprintf(stdout, "%s ", inBuf);

data = atoi(inBuf);

//So add a new node & fill it with data

if (NULL == root) // First node add to the list

{

root = addToList(root, data);

}

else

{ // add to the bottom of the list

temp = addToList(root, data);

if (NULL == temp)

{

printf("Failed to add - good bye ");

return -1;

}

}

}

printList(root);

fclose(ifp);

return 0;

}

/*

* The sample input file is based on the included "booyah2.txt"

* file.

* New input file with commands. (Note the comments are for

* clarification and are NOT a requirement for this program.)

---Begin sample booyah2.txt

i 23 // insert 23

i 78 // insert 78

i 900 // insert 900 //remember if not two number the first is addToList only

i 23 42 // insert 42 after 23

p // print

f 78 // find 78

d 78 // delete 78

p // print

i 905 47 // insert 47 after 905 (failure: no afterData)

f 901 // find 901 (failure case test)

p //print

---End sample booyah2.txt

*/