Data structure unidirectional linked list

As shown in the diagram, the Single chain table node has two fields: the pointer field and the data field are defined as follows:

typedef int DATATYPE;
Class Node {
	friend class NodeList;   
Private:
	dataType data;   Data domain
	node* link;      Pointer field  A pointer to the next element
};

Also has a node-linked list for storing data: defined as follows

Class NodeList {
private:
	node* first;    Head node pointer public
:
	nodeList () {first = 0;}

	void Add (DataType num);           Add
	void Inserttail (DataType num) sequentially from the head of the list;    Connection to tail
	void Mediuminsert (dataType num, int pos);
	void Delete (DataType num);   Delete a value
	void Show ();
};

Traverse the entire list through the pointer:

void Nodelist::show () {
	node* P = new node ();     
	p = First;              Point to the first node while
	(P! = NULL) {
		DataType temp = p->data;
		cout << temp << "   ";
		p = p->link;    Data Iteration
	}
	cout << Endl;
}

Add a new node:

void Nodelist::add (DataType num) {
	node* NewNode = new node ();    Create a new node
	newnode->data = num;           
	
	Newnode->link = First;     The pointer field of the new node points to the next node first
	= NewNode;          New node marked as head node

}

Insert to Trailer:

void Nodelist::inserttail (DataType num) {
	///new node
	node* newNode = "n" ();
	Newnode->data = num;

	Used to traverse
	node* p = new node ();   
	p = First;

	while (p->link! = NULL) {
		p = p->link;
	}

	Newnode->link = p->link;  Tail Insertion method
	P->link = NewNode;
	
}

There is no difference between intermediate and trailing inserts just iterate to the specified location and insert the operation

interpolation
void Nodelist::mediuminsert (dataType num, int pos) {
	node* NewNode = new node ();
	Newnode->data = num;  

	node* p = new node ();
	p = First;
	int k = 1;   Mark Node Location
	

	while (p->link! = NULL && K < pos-1) {
		p = p->link;
		k++;
	}

	Newnode->link = p->link;  
	P->link = NewNode;        
}

Delete operation:

void NodeList::D elete (DataType num) {
	
	node* P = new node ();   The first pointer
	node* q = new node ();   The second pointer
	p = first;
	Q = NULL;
	
	if (p = = NULL) {         
		return;
	}

	if (p->data = = num) {   //determine if the first node is the node to be deleted.
		

                Delete p;        Delete node
		return; 
	}
	else {
		//start traversing
		while (P! = NULL) {
			q = p;
			q = q->link;
			if (q->data = = num) {
				P->link = q->link;
				Delete q;
				break;
			}
			p = p->link;
		}}}