﻿ C++ - Delete the nth node of a Singly Linked List from end

# C++ Linked List Exercises: Delete the nth node of a Singly Linked List from end

## C++ Linked List: Exercise-13 with Solution

Write a C++ program to delete the nth node of a Singly Linked List from the end.

Test Data:
Original list:
7 5 3 1
Remove the 2nd node from the end of the said list:
Updated list:
7 5 1
Remove the 3rd node from the end of the said list:
Updated list:
5 1

Sample Solution:

C++ Code:

``````  #include <iostream> // Including input-output stream header file

using namespace std; // Using standard namespace

struct Node // Declare a structure for defining a Node
{
int num; // Data field to store a number
Node *next; // Pointer to the next node
}; // Node constructed

int sizen = 0; // Initializing variable to keep track of the size of the linked list

// Function to insert a node at the start of the linked list
Node* new_Node = new Node(); // Creating a new node
new_Node->num = num; // Assigning data to the new node
new_Node->next = *head; // Pointing the new node to the current head
sizen++; // Increasing the size of the linked list
}

// Function to delete the nth node from the end of the linked list
Node* delete_last_node(Node* head, int n) {
while (n--) q = q->next; // Moving q 'n' nodes ahead from head
if (!q) return head->next; // If q reaches the end, remove the first node
while (q->next) { // Until q reaches the end
p = p->next; // Move p forward
q = q->next; // Move q forward
}
Node* toDelete = p->next; // Node to be deleted
p->next = p->next->next; // Deleting the node
delete toDelete; // Freeing the memory of the deleted node
}

// Function to display all nodes in the linked list
void display_all_nodes(Node* node)
{
while(node != NULL){ // Loop through all nodes until the end is reached
cout << node->num << " "; // Displaying the data in the current node
node = node->next; // Move to the next node
}
}

int main()
{

insert(&head,1); // Inserting a node with value 1
insert(&head,3); // Inserting a node with value 3
insert(&head,5); // Inserting a node with value 5
insert(&head,7); // Inserting a node with value 7

cout << "Original list:\n"; // Displaying message for the original list
display_all_nodes(head); // Displaying all nodes in the original list

int pos = 2; // Position of the node to be removed from the end
cout << "\n\nRemove the " << pos << "nd node from the end of the said list:";
cout << "\nUpdated list:\n";
display_all_nodes(head); // Displaying all nodes after removal

pos = 3; // Position of the node to be removed from the end
cout << "\n\nRemove the " << pos << "rd node from the end of the said list:";
cout << "\nUpdated list:\n";
display_all_nodes(head); // Displaying all nodes after removal

cout << endl; // Displaying newline
return 0; // Returning from the main function
}
``````

Sample Output:

```Original list:
7 5 3 1

Remove the 2nd node from the end of the said list:
Updated list:
7 5 1

Remove the 3rd node from the end of the said list:
Updated list:
5 1
```

Flowchart:

CPP Code Editor: