Linked List Example

A Multiple File Application

File: node.h

// node.h

#ifndef NODE_H
#define NODE_H

#include <iostream>

class Node
{
    int    data;
    Node*    next;
public:
    Node(int d,Node* n);
    int get_data() const;
    Node* get_next() const;
    void set_next(Node* ptr);
};

std::ostream& operator<<(std::ostream&, const Node&);

#endif

File: list.h

// list.h

#ifndef LIST_H
#define LIST_H

#include "node.h"
#include <iostream>

class List
{
    Node*    top;
public:
    List();
    ~List();
    void push(int item);
    int pop();
    Node* get_top() const;
    bool remove(int item);
    Node*    find(int item) const;
    bool remove_last();
};

std::ostream& operator<<(std::ostream&, const List&);

#endif

File: node.cpp

#include "node.h"
#include <iostream>
using namespace std;

Node::Node(int d,Node* n)
    : data(d), next(n)
{ }

int Node::get_data() const
{
    return data;
}

Node* Node::get_next() const
{
    return next;
}

void Node::set_next(Node* ptr)
{
    next = ptr;
}

ostream& operator<<(ostream& out, const Node& obj)
{
    out << obj.get_data();
    return out;
}

File: list.cpp

#include <iostream>
#include <cstdlib>
#include <climits>    // for INT_MAX
using namespace std;

#include "list.h"

List::List() : top(0)
{ }

List::~List()
{
    Node* temp = top;
    while (temp != nullptr)
    {
        top = top -> get_next();
        delete temp;
        temp = top;
    }
}

void List::push(int item)
{
    Node* temp = new Node(item,top);
    top = temp;
}

int List::pop()
{
    if (!top)
    {
        cout << "List is empty" << endl;
        return INT_MAX;
    }
    Node* temp = top;
    top = top->get_next();
    int value = temp->get_data();
    delete temp;
temp = nullptr;
    return value;
}

Node* List::get_top() const
{
    return top;
}

Node*    List::find(int item) const
{
    if (!top) return nullptr;
    Node* temp = top;
    while (temp != nullptr)
    {
        if (temp->get_data() == item)
            return temp;
        temp = temp -> get_next();
    }
    return nullptr;
}

bool List::remove(int item)
{
    if (!find(item))
    {
        cerr << item << " is not in the List\n";
        return false;
    }
    Node* temp1 = top;
    Node* temp2;
    if (top->get_data() == item)
    {
        top = top -> get_next();
        delete temp1;
temp1 = nullptr;
        return true;
    }
    while (temp1->get_next()->get_data() != item)
    {
        temp1 = temp1 -> get_next();
    }
    temp2 = temp1 -> get_next();
    temp1->set_next(temp2->get_next());
    delete temp2;
temp2 = nullptr;
    return true;
}

ostream& operator<<(ostream& out, const List& object)
{
    Node* temp = object.get_top();
    while (temp != 0)
    {
        out << *temp << ' ';
        temp = temp -> get_next();
    }
    return out;
}

File: main.cpp

#include <iostream>
#include <climits>    // for INT_MAX
using namespace std;

#include "list.h"

int main()
{
    List L;
    L.push(2);
    L.push(4);
    L.push(6);
    L.push(8);
    L.push(10);
    cout << L << endl;

    if (L.get_top())
        cout << "top value is " << L.get_top()->get_data() << endl;

    if (L.find(2))
        cout << 2 << " is in the list\n";
    if (L.find(5))
        cout << 5 << " is in the list\n";
    if (L.find(6))
        cout << 6 << " is in the list\n";
    if (L.find(10))
        cout << 10 << " is in the list\n";

    int popReturn = L.pop();
    if (popReturn == INT_MAX)
        cout << "list is empty" << endl;
    cout << popReturn << " removed from the list" << endl;

    L.remove(3);
    L.remove(6);
    cout << L << endl;

    L.remove(2);
    L.remove(8);
    cout << L << endl;
}

OUTPUT:

10 8 6 4 2
top value is 10
2 is in the list
6 is in the list
10 is in the list
10 removed from the list
8 6 4 2
3 is not in the List
8 4 2
4