Searching a string in a linked list C - c

Question

I am having issues searching a linked list in C. I manage to search and find an integer entry but am having problems with strings (first and last names). Basically, there are three functions that search a telephone directory for entries by first, last name and number. Would it be possible to display the entry when a search is found too? Please find the code below. Thanks for your help.
struct node {
char firstname[32];
char lastname[32];
int *number;
struct node *next;
}*head;
struct node *start=NULL;
struct node *getnode() {
return((struct node *)malloc(sizeof(struct node)));
}
void insert() {
struct node *temp,*nn;
nn=getnode();
temp=start;
while(temp->next!=NULL)
{
temp=temp->next;
}
printf("Enter First name:\n");
scanf("%s",&nn->firstname);
printf("Enter Last name:\n");
scanf("%s",&nn->lastname);
printf("Enter number:\n");
scanf("%d",&nn->number);
temp->next=nn;
nn->next=NULL;
display(start);
}
struct node *create() {
struct node *temp,*nn;
if(start!=NULL) insert();
else {
nn=getnode();
start=nn;
temp=start;
printf("Enter First name:\n");
scanf("%s",&nn->firstname);
printf("Enter Last name:\n");
scanf("%s",&nn->lastname);
printf("Enter number:\n");
scanf("%d",&nn->number);
nn->next=NULL;
}
}
void searchByFirstName() {
char *f;
struct node* temp, *nn;
temp = start;
while (temp != NULL){
printf("Enter First Name to be searched:\n"); scanf("%s",&f);
printf("%s", &f);
if (temp -> firstname == f){
printf ("\n Record Found!\n");
temp = temp -> next;
}else{
printf ("\n Record not found\n");
}
}
}
void searchByLastName() {
char *f;
struct node* temp, *nn;
temp = start;
if (temp != NULL){
printf("Enter Last Name to be searched:\n"); scanf("%s",&f);
printf("%s", &f);
if (temp -> lastname == f){
printf ("\n Record Found!\n");
temp = temp -> next;
}else{
printf ("\n Record not found\n");
}
}
}
void searchByNumber() {
int *l;
struct node* temp, *nn;
temp = start;
if (temp != NULL){
printf("Enter Number to be searched:\n"); scanf("%d",&l);
if (temp -> number == l){
printf ("\n Record Found!\n");
temp = temp -> next;
}else{
printf ("\n Record not found\n");
}
}
}

Answer 1

In C, you cannot just compare two strings (aka char *) using operator ==. When you work with strings in C, you can use the standard functions (#include <string.h>), like:
strcmp(temp->lastname, f) // returns 0 in case of a perfect match

Answer 2

2nd EDIT: added Pretty functions (last section) - examples of how printing messages could be modified.
EDIT: added free(l) in the searchByNumber2(), fixing a memory leak
For the thing you was asking for:
void searchByLastName() {
char f = char[32];
struct node* temp, *nn;
temp = start;
printf("Enter Last Name to be searched:\n"); scanf("%s",f);
printf("%s", f);
while (temp != NULL){//!we search through whole list
if (strcmp(temp -> lastname, f) == 0) {
printf ("\n Record Found!\n");
temp = temp -> next;
}else{
printf ("\n Record not found\n");
/*!you probably wanna pull this printf for after the loop;
I would either add bool Found and add if after the loop
or after the loop always print "search finished" or sth */
}
}
}
And two versions of fixed searching by numbers (the second uses int *l, as an example; the first uses int l and is cleaner)
void searchByNumber() {
int l;
struct node* temp, *nn;
temp = start;
printf("Enter Number to be searched:\n"); scanf("%d",&l);//&l is address of the int l
while (temp != NULL){
if (*(temp -> number) == l){//notice: temp->number is a pointer to int, not an int itself, l is an int here
printf ("\n Record Found!\n");
temp = temp -> next;
}else{
printf ("\n Record not found\n");
}
}
}
void searchByNumber2() {
int *l = malloc(sizeof int);
struct node* temp, *nn;
temp = start;
printf("Enter Number to be searched:\n"); scanf("%d",l);
while (temp != NULL){
if (*(temp -> number) == *l){//we want to compare int values, not their adresses, both temp->number and l are pointers here
printf ("\n Record Found!\n");
temp = temp -> next;
}else{
printf ("\n Record not found\n");
}
}
free(l);
}
Last edit
Note: this version of searchByLastNamePretty prints Found message the number of times the last name appears, and prints Finished message after a search.
On th other hand, searchByNumberPretty prints a Found message or a Not-Found message (only one message, always; doesn't matter if there is a lot of occurences of the number).
Use them as examples of what you could do. Analyze usage of bool Found.
void searchByLastNamePretty() {
char f = char[32];
struct node* temp, *nn;
temp = start;
printf("Enter Last Name to be searched:\n"); scanf("%s",f);
printf("%s\n", f); //better practice, to end printf with \n to flush it
while (temp != NULL){//!we search through whole list
if (strcmp(temp -> lastname, f) == 0) {
printf ("Record Found!\n");
temp = temp -> next;
}
printf("Search finished\n");
}
}
void searchByNumberPretty() {
int l;
struct node* temp, *nn;
temp = start;
printf("Enter Number to be searched:\n");
scanf("%d",&l);//&l is address of the int l
bool found = false;
while (temp != NULL && !found){//!we search till the first occurence
if (*(temp -> number) == l){//note: (temp->number) is a pointer to int, not an int
found = true;
temp = temp -> next;
}
}
if (found) {
printf("Record Found!\n");
}
else {
printf("Record not found\n");
}
}