linked-list.cpp

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


class Node {
	public:
		double data;
		Node* next;
};

class List {
	public:  
		List(void) { head = NULL; } // constructor
		~List(void);    // destructor  
 		bool IsEmpty() { return head == NULL; }  
		Node* InsertNode(double x);   
		int FindNode(double x);   
		int DeleteNode(double x);  
		void DisplayList(void); 
	private:
		Node* head; 
};

Node* List::InsertNode(double x) {    
	int currIndex = 0;  
	Node* currNode = head;  
	Node* prevNode = NULL;  
	while (currNode && x > currNode->data) 
	{   prevNode = currNode;                currNode = currNode->next;   currIndex++;  }    
	Node* newNode = new Node;  
	newNode->data = x;   
	if (currIndex == 0) {   newNode->next = head;   head  = newNode;  }
	else {   newNode->next = prevNode->next;   prevNode->next = newNode;  }  
	return newNode; 
}

int List::FindNode(double x) {  
	Node* currNode = head;  
	int currIndex = 1;  
	while (currNode && currNode->data != x) {   currNode = currNode->next;   currIndex++;  }  
	if (currNode)    
		return currIndex; 
	else   
		return 0; 
} 

void List::DisplayList() {    
	int num  = 0;    
	Node* currNode = head;    
	while (currNode != NULL){  cout << currNode->data << endl;  currNode = currNode->next;  num++;    }    
	cout << "Number of nodes in the list: " << num << endl; 
}

int List::DeleteNode(double x) {  
	Node* prevNode = NULL;  
	Node* currNode = head;  
	int currIndex = 1;  
	while (currNode && currNode->data != x) 
	{   
		prevNode = currNode;   
		currNode = currNode->next;   
		currIndex++;  
	}  
	if (currNode) {   
		if (prevNode) {    
			prevNode->next = currNode->next;    
			delete currNode;   
		}   else {    head  = currNode->next;    delete currNode;   }   
		return currIndex;  
		}  
return 0; } 

List::~List()  {  
	Node* currNode = head, 
	*nextNode = NULL;    
	while (currNode != NULL)    { 
		nextNode = currNode->next;  // destroy the current node  
		delete currNode;   
		currNode = nextNode;    
	}    
	head = NULL; 
}

int main(void) {  
	List list;  
	list.InsertNode(7.0); // successful  
	list.InsertNode(5.0); // successful  
	list.InsertNode(6.0); // successful  
	list.InsertNode(4.0); // successful  
	// print all the elements  
	list.DisplayList();     
	if(list.FindNode(5) > 0) 
		cout << "5 found" << endl;   
	else    
		cout << "5 not found" << endl;  
	
	if(list.FindNode(4.5) > 0) 
		cout << "4.5 found" << endl;  
	else    
		cout << "4.5 not found" << endl;  
	list.DeleteNode(7.0);  
	list.DisplayList();  
	getch();
return 0; }