Question

I need help with C++. I want to create a function that will remove all target nodes in a single linked list.

Answer 1

`Hey,

Note: If you have any queries related the answer please do comment. I would be very happy to resolve all your queries.

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#include <iostream>
#include <stdlib.h>

using namespace std;

// A linked list node
struct Node
{
int data;
struct Node *next;
};
  
/* Given a reference (pointer to pointer) to the head of a list
and an int, inserts a new node on the front of the list. */
void push(struct Node** head_ref, int new_data)
{
struct Node* new_node = (struct Node*) malloc(sizeof(struct Node));
new_node->data = new_data;
new_node->next = (*head_ref);
(*head_ref) = new_node;
}
  
/* Given a reference (pointer to pointer) to the head of a list and
a key, deletes all occurrence of the given key in linked list */
void deleteKey(struct Node **head_ref, int key)
{
// Store head node
struct Node* temp = *head_ref, *prev;
  
// If head node itself holds the key or multiple occurrences of key
while (temp != NULL && temp->data == key)
{
*head_ref = temp->next; // Changed head
free(temp); // free old head
temp = *head_ref; // Change Temp
}
  
// Delete occurrences other than head
while (temp != NULL)
{
// Search for the key to be deleted, keep track of the
// previous node as we need to change 'prev->next'
while (temp != NULL && temp->data != key)
{
prev = temp;
temp = temp->next;
}
  
// If key was not present in linked list
if (temp == NULL) return;
  
// Unlink the node from linked list
prev->next = temp->next;
  
free(temp); // Free memory
  
//Update Temp for next iteration of outer loop
temp = prev->next;
}
}
  
// This function prints contents of linked list starting from
// the given node
void printList(struct Node *node)
{
while (node != NULL)
{
cout<<" "<<node->data<<" ";
node = node->next;
}
}
  
/* Driver program to test above functions*/
int main()
{
/* Start with the empty list */
struct Node* head = NULL;
  
push(&head, 7);
push(&head, 2);
push(&head, 3);
push(&head, 2);
push(&head, 8);
push(&head, 1);
push(&head, 2);
push(&head, 2);
  
int key = 2; // key to delete
  
cout<<("Created Linked List: ");
printList(head);
  
deleteKey(&head, key);
cout<<("\nLinked List after Deletion of all nodes with value 2: ");
  
printList(head);
return 0;
}

Kindly revert for any queries

Thanks.