Delete string from linked list - C [duplicate] - c

Question

This question already has an answer here:
Delete element of linked list by a certain criterion
(1 answer)
Closed 7 years ago.
So the problem I'm running into is deleting a user-inputted string from a linked list full of strings.
I'm still having a few issues in understanding just precisely how linked lists work, so any explanation as to what I am doing wrong would be greatly appreciated!
Also, every other function seems to be working just fine, just having issues with the deleteItem function!
Edit - The problem I'm getting when I run the deleteItem function is just my terminal window crashing after getting hung up for a bit.
Here's my code:
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
struct node
{
char name[50];
struct node *next;
}*head;
void display();
void insert();
void count();
void deleteItem();
int main(){
int choice = 1;
char name[50];
struct node *first;
head = NULL;
while(1){
printf("Menu Options\n");
printf("----------------\n");
printf("Please enter the number of the operation you'd like to do: \n");
printf("----------------\n");
printf("1. Insert\n");
printf("2. Display\n");
printf("3. Count\n");
printf("4. Delete\n");
printf("5. Exit\n");
printf("----------------\n");
scanf("%d",&choice);
switch(choice)
{
case 1:
insert();
break;
case 2:
display();
break;
case 3:
count();
break;
case 4:
if(head=NULL)
printf("The list is blank");
else
deleteItem();
break;
case 5:
return 0;
default:
printf("invalid option");
}
}
system("pause");
return 0;
}
void insert(){
char nameToInsert[50];
struct node *temp;
temp = head;
if(head == NULL){
head = (struct node *)malloc(sizeof(struct node));
printf("What's the name you wish to insert?\n");
scanf("%s", &nameToInsert);
strcpy(head->name, nameToInsert);
head->next = NULL;
}
else{
while(temp->next !=NULL){
temp = temp->next;
}
temp->next = malloc(sizeof(struct node));
temp = temp->next;
printf("What's the name you wish to insert?\n");
scanf("%s", &nameToInsert);
strcpy(temp->name, nameToInsert);
temp->next = NULL;
}
}
void display(){
struct node *temp;
temp = (struct node *)malloc(sizeof(struct node));
temp = head;
if(temp == NULL)
printf("The list is empty\n");
else{
printf("%s\n", temp->name);
while(temp->next != NULL){
temp = temp->next;
printf("%s\n", temp->name);
}
}
}
void count(){
struct node *temp;
int c =0;
temp = head;
while(temp!=NULL){
temp=temp->next;
c++;
}
printf("\n%d", c);
}
void deleteItem(){
char nameToDelete[50];
struct node *temp, *previous;
temp = head;
printf("What is the name you wish to delete?\n");
scanf("%s", nameToDelete);
while(temp->next != NULL){
temp = temp->next;
if(strcmp(nameToDelete, temp->name)==0){
previous = temp->next;
free(temp);
printf("%s was deleted successfully\n", nameToDelete);
}
}
}

Answer 1

I see the following issues:
You are not dealing with the case where the item to delete is at the head of the list.
The linked list is not restored to a good state after you free the node that contains the item.
You continue to iterate over the list even after you free the node that contains the item.
Here's a version that should work.
void deleteItem(){
char nameToDelete[50];
struct node *temp, *previous;
temp = head;
printf("What is the name you wish to delete?\n");
scanf("%s", nameToDelete);
// First, locate the node that contains the item.
for ( ; temp->next != NULL; temp = temp->next )
{
if(strcmp(nameToDelete, temp->name)==0)
{
break;
}
prev = temp;
}
// Now take care of deleting it.
if ( temp != NULL )
{
if ( temp == head )
{
head = temp->next;
}
else
{
prev->next = temp->next;
}
free(temp);
printf("%s was deleted successfully\n", nameToDelete);
}
}