Question

Can someone please tell me on how can I have a double and character as one of the items on my list? Thanks!
This is what I got so far and the values I am getting are all integers.

#pragma once
#include <iostream>

class Node
{
public:
   int data;
   Node* next;       // self-referential

   Node()
   {
       data = 0;
       next = nullptr;
   }

   Node(int value)
   {
       data = value;
       next = nullptr;
   }

   ~Node()
   {
       if (next != nullptr)
           delete next;

       // DEBUG:
       std::cout << "Deleting " << data << std::endl;

   }
};

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

class LinkedList
{
private:
Node* first;
public:
LinkedList()
{
first = new Node();
}

~LinkedList()
   {
       delete first;
   }

   bool isEmpty()
   {
       return first->next == nullptr;
   }

   void addFront(int value)
   {
       Node* newNode = new Node(value);
       newNode->next = first->next;
       first->next = newNode;
   }

   void addBack(int value)
   {
       Node* t = first; // traversal pointer

       // find the end of the list
       while (t->next != nullptr)
           t = t->next;

       // attach new node
       t->next = new Node(value);
   }

   void removeFront()
   {
       Node* t = first->next;

       first->next = t->next;

       t->next = nullptr;
       delete t;
   }

   void removeBack()
   {
       if (isEmpty()) return;

       Node* trailer = first;
       Node* trav = first->next;

       while (trav->next != nullptr)
       {
           trav = trav->next;
           trailer = trailer->next;
       }

       trailer->next = nullptr;
       delete trav;
   }

   void display()
   {
       Node* t = first->next;

       while (t != nullptr)
       {
           std::cout << t->data << " ";
           t = t->next;
       }
       std::cout << std::endl;
   }

   Node* find(int value)
   {
       Node* t = first->next;

       while (t != nullptr)
       {
           if (t->data == value)
               return t;
           t = t->next;
       }

       return nullptr;
   }

   void duplicate()
   {
       Node* temp = first->next;

       while (temp != nullptr)
       {
           int key = temp->data;
           Node* trailer = temp;
           Node* searchPtr = temp->next;
           while (searchPtr != nullptr)
           {
               if (searchPtr->data == key)
               {
                   trailer->next = searchPtr->next;
                   searchPtr->next = nullptr;
                   delete searchPtr;
                   searchPtr = trailer->next;
               }
               else
               {
                   trailer = trailer->next;
                   searchPtr = searchPtr->next;
               }
           }
           temp = temp->next;
       }
   }

};

template <class T>
class Data
{
private:
   T value;

public:
   T get()
   {
       return value;
   }

   void set(T data)
   {
       value = data;
   }
};

int main()
{
   LinkedList list;

   Data<int> intData;
   Data<double> doubleData;
   Data<char> charData;
  

   intData.set(25);
   doubleData.set(14.82);
   charData.set('K');
  

   if (list.isEmpty()) cout << "List is empty.\n";
   else cout << "List contains data.\n";
  
   for (int x = 0; x < 2; x++)
   {
           list.addFront(intData.get());
           list.addBack(charData.get());
           list.addFront(doubleData.get());
   }
  

   if (list.isEmpty()) cout << "List is empty.\n";
   else cout << "List contains data.\n";

   cout << "List contents: ";
   list.display();

   cout << "\nFind a value\n";
   cout << "Enter a value to search: ";
   int key;
   cin >> key;

   Node* p = list.find(key);
   if (p == nullptr)
       cout << "Did not find " << key << endl;
   else
       cout << "Found " << key << " at " << p << endl << endl;

   cout << "Removing duplicates...\n";
   list.duplicate();

   list.display();

   cout << endl << "Removing front...\n";
   list.removeFront();
   list.display();

   cout << "\nRemoving back...\n";
   list.removeBack();

   list.display();
}

Answer 1

Hi

Step 1 : Please add template keyword above the class Node as shown

Step 2 : change the data type from int to T, as done below

template <typename T>

class Node
{
public:
   T data;
   Node* next;       // self-referential

   Node()
   {
       data = 0;
       next = nullptr;
   }

   Node(T value)
   {
       data = value;
       next = nullptr;
   }

   ~Node()
   {
       if (next != nullptr)
           delete next;

       // DEBUG:
       std::cout << "Deleting " << data << std::endl;

   }
};

Step 3: add template <typename T> above

void addFront(int value)

void addBack(int value)

void addBack(int value)

Step4: Replace the calls to above functions with template calls passing data types

I hope you got the information, kindly let me know for any clarifications

Thanks