Linked List

[robjs111]

Working on inserting a node at the front of linked list. First time I ran code worked perfect but now no good.
Thanks

  #include<iostream>
using namespace std;

class Node
{
public:
	int value;
	Node* Next;
};

void printlist(Node* n)
{
	while(n!= NULL)
	{
		cout << n->value << endl;
		n = n->Next;
	}
}
void insertAtFront(Node** head, int newvalue)
{	
	Node* newNode = new Node();
	newNode->value = newvalue;
	newNode->Next = *head;
	*head = newNode;
}



int main()
{
	Node* head = new Node();
	Node* second = new Node();
	Node* third = new Node();
	Node* fourth = new Node();

	head->value = 1;
	head->Next = second;
	second->value = 2;
	second->Next = third;
	third->value = 3;
	third->Next = fourth;
	fourth->value = 4;
	fourth->Next = NULL;

	printlist(head);
	insertAtFront(&head, -1);
	//insertAtFront(&head, -2);




	system("pause>0");
}

[seeplus]

Try this:

#include <iostream>
using namespace std;

class Node
{
public:
	int value {};
	Node* Next {};
};

void printlist(const Node* n)
{
	for (; n != nullptr; n = n->Next)
		cout << n->value << '\n';

	cout << '\n';
}

void insertAtFront(Node*& head, int newvalue)
{
	auto newNode {new Node()};

	newNode->value = newvalue;
	newNode->Next = head;
	head = newNode;
}

int main()
{
	Node* head {};

	insertAtFront(head, -1);
	insertAtFront(head, -2);
	insertAtFront(head, -3);
	insertAtFront(head, -4);

	printlist(head);
}

which displays:

-4
-3
-2
-1

[robjs111]

Thanks for the code.

Do you see any issues with my code so far? First time I ran code -1 printed in front of 1 but second run nothing printed except 1 - 4.
Any ideas?

[seeplus]

Well there's no printlist() after the insertAtFront() ??

Adding that, and slightly changing the display format:

#include<iostream>
using namespace std;

class Node
{
public:
	int value;
	Node* Next;
};

void printlist(Node* n)
{
	while (n != NULL)
	{
		cout << n->value << endl;
		n = n->Next;
	}

	cout << '\n';
}

void insertAtFront(Node** head, int newvalue)
{
	Node* newNode = new Node();
	newNode->value = newvalue;
	newNode->Next = *head;
	*head = newNode;
}

int main()
{
	Node* head = new Node();
	Node* second = new Node();
	Node* third = new Node();
	Node* fourth = new Node();

	head->value = 1;
	head->Next = second;
	second->value = 2;
	second->Next = third;
	third->value = 3;
	third->Next = fourth;
	fourth->value = 4;
	fourth->Next = NULL;

	printlist(head);
	insertAtFront(&head, -1);
	insertAtFront(&head, -2);
	printlist(head);

	//system("pause>0");
}

1
2
3
4

-2
-1
1
2
3
4

[robjs111]

ah
its usually something that basic that i overlook.
Thanks Seeplus for all your help