###################################### My code is below, I just want someone can

Question

######################################

My code is below, I just want someone can varify and fix my code if I was wrong.

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#include <iostream>

using namespace std;

struct Node {
int data;
Node *previous, *next;
};

void insertAfter(Node *, int);

int main(){
Node *current;
insertAfter(current, 5)
break;
}

void insertAfter(Node *current,int value)
{
struct Node *newNode;
newNode = (struct Node*)malloc(sizeof(struct Node));
newNode->data = value;

if(current->previous = NULL)
{
newNode->previous = NULL;
newNode->next = current;
current->previous = newNode;
}
}

Suppose we have a Node struct with previous and next members of type Node along with a member int data. We wish to insert the value 5 right before the value in the node pointed to by Node *current (which is assumes to be non null). Write several statements that accomplish this. Here is the declaration for Node: struct Node int data; Node previous, "next You'll need to allocate the node object to be inserted using new and assign 5 to it's data member as well as give appropriate values to its previous and next pointers to link things up correctly. Be mindful of the case where current is at the beginning of the list, so current->previous will be null.

Explanation / Answer

#include <iostream>
#include <stdlib.h>
using namespace std;

// Creates a structure for Node
struct Node
{
// To store data
int data;
// To point to next and previous node
Node *previous, *next;
};// End of structure

// To insert a node after the current node
void insertAfter(Node *current, int value)
{
// Checks if the given current node is NULL
if (current == NULL)
{
cout<<" ERROR: The given current node cannot be NULL";
return;
}

// Dynamically allocate memory to newNode
struct Node* newNode =(struct Node*) malloc(sizeof(struct Node));

// Assigns parameter value to new node data part
newNode->data = value;

// Make next of new node as next of current node
newNode->next = current->next;

// Move the next of current node as new node
current->next = newNode;

// Make current as previous of new_node
newNode->previous = current;

// Change previous of new_node's next node
if (newNode->next != NULL)
newNode->next->previous = newNode;
}// End of function

// Function to display list information
void display(struct Node *node)
{
// Loops till end of the list
while (node != NULL)
{
// Displays each node value with comma
cout<<node->data<<", ";
// Move next
node = node->next;
}// End of while loop
}// End of function

// Function to add a node at the end
void addFront(struct Node** head, int value)
{
// Dynamically allocates memory to new node
struct Node* newNode = (struct Node*)malloc(sizeof(struct Node));
// Assigns parameter value to new node data part
newNode->data = value;
// New node next points to head
newNode->next = (*head);
// Assigns NULL to new node previous
newNode->previous = NULL;
// Checks if head is not NULL
if ((*head) != NULL)
// Assigns new node to head previous
(*head)->previous = newNode;
// Assigns new node to head
(*head) = newNode;
}// End of function

// main function to new node
int main()
{
// Creates a head node assigns NULL to it
struct Node* head = NULL;

// Calls the function to add at front
addFront(&head, 66);
addFront(&head, 26);
addFront(&head, 16);
addFront(&head, 6);
// Calls the function to display the list
display(head);
// Creates a current node which is points to head next node
struct Node *current = head->next;
cout<<" Display from current: ";
// Calls the function to display the list
display(current);
// Calls the function to inset a node after the current node
insertAfter(current, 5);
cout<<" Display from had inserting 5 after current: ";
// Calls the function to display the list
display(head);
return 0;
}// End of main function

Sample Output:

6, 16, 26, 66,
Display from current: 16, 26, 66,
Display from had inserting 5 after current: 6, 16, 5, 26, 66,

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