gistfile1.txt

#include <iostream>
#include <cstdlib>
#include <memory>

using namespace std;  
  
/* Link list node */
class Node
{
public: 
	int key;  
	Node* next;
};  

class NodeUtils
{
public:
	void
	push(Node** head_ref, int new_key)  
	{  
	    /* allocate node */
	    Node* new_node = new Node(); 
  
	    /* put in the key */
	    new_node->key = new_key;  
  
	    /* link the old list off the new node */
	    new_node->next = (*head_ref);  
  
	    /* move the head to point to the new node */
	    (*head_ref) = new_node;  
	}  
  
	void
	listall(Node* head)  
	{  
		Node* current = head;

		while(current != nullptr) {
			cout << current->key;
			current = current->next;
			if(current != nullptr) cout << ", ";
		}
		cout << endl;
	}

	/* searches for the value x in linked list */
	Node*
	search(Node* head, int x)  
	{  
	    Node* current = head;
	    while(current != nullptr) {  
	        if (current->key == x)  
	            return current;  
	        current = current->next;  
	    }  
	    return nullptr;  
	}

	unsigned
	count(Node* head)
	{
		Node* current = head;
		unsigned count = 0;
		
		while(current != nullptr) {
			current = current->next;
			count++;
		}

		return count;
	}

	void
	sortasc(Node* head)
	{
		Node* temphead = head;
		int tempkey;
		unsigned counter = count(head);

		for(unsigned n = 0; n < counter; n++) {
			while(temphead->next) {
				if(temphead->key > temphead->next->key) {		
					tempkey = temphead->key;

					temphead->key = temphead->next->key;
					temphead->next->key = tempkey;
				}
				temphead = temphead->next;
			}
			temphead = head;
		}
	}

	void sortdsc(Node* head)
	{
		Node* temphead = head;
		int tempkey;
		unsigned counter = count(head);

		for(unsigned n = 0; n < counter; n++) {
			while(temphead->next) {
				if(temphead->key < temphead->next->key) {		
					tempkey = temphead->key;

					temphead->key = temphead->next->key;
					temphead->next->key = tempkey;
				}
				temphead = temphead->next;
			}
			temphead = head;
		}
	}

	Node*
	deletefirst(Node* head)
	{
		Node* temp = new Node;
		temp = head;
		head = head->next;

		delete temp;
		return head;
	}

	void
	deletelast(Node* head)
	{
		Node* current = new Node;
		Node* previous = new Node;
		current = head;

		while(current->next != nullptr) {
			previous = current;
			current = current->next;  
		}

		previous->next = nullptr;
		delete current;
	}

	bool
	deletevalue(Node* head, int val)
	{
		Node* temp = head;
		if(head->key == val) {
			head = head->next;
			delete temp;
		}

		while(temp->next != nullptr && temp->next->key != val)
			temp = temp->next;

		if(temp->next == nullptr)
			return false;
		else {
			if(temp->next->key == val) {
				Node* remove = temp->next;
				temp->next = temp->next->next;
				delete remove;
			}
		}
		return true;
	}
};

int
main(int argc, char** argv)  
{  
    /* Start with the empty list */
	unique_ptr<NodeUtils> utl = make_unique<NodeUtils>();
	Node* head = nullptr;  

	utl->push(&head, 10);  
	utl->push(&head, 30);  
	utl->push(&head, 11);  
	utl->push(&head, 21);  
	utl->push(&head, 14);
	utl->push(&head, 22);  
	utl->push(&head, 56);  
 	utl->push(&head, 57);  
	utl->push(&head, 104);

 	utl->search(head, 21)? cout << "Node found" << endl :
		cout << "Node not found" << endl;

	utl->listall(head);
	cout << "number of elements: " << utl->count(head) << endl;
	utl->sortasc(head);

	cout << endl << "Sorted ascending:" << endl;
	utl->listall(head);
	utl->sortdsc(head);

	cout << endl << "Sorted descending:" << endl;
	utl->sortdsc(head);
	utl->listall(head);

	cout << endl << "Deleteing head node: " << head->key << endl;
	head = utl->deletefirst(head);
	utl->listall(head);

	cout << endl << "Searching for 14" << endl;
	(utl->search(head, 14) != nullptr)? cout << "Found" << endl :
		cout << "Not found" << endl;

	cout << endl << "Deleting tail" << endl;
	utl->deletelast(head);
	utl->listall(head);

	cout << endl << "Deleting node valued 14" << endl;
	utl->deletevalue(head, 14);
	utl->listall(head);

	return EXIT_SUCCESS;  
}  

Push down list I wrote for a prospective employer. They didn't hire me.