Question

i created a linked list : struct Node and List Class and i used it outside with my main method,

#include "Lists.cpp"
#include <cstdlib>
using namespace std;

int main(){


    Lists l = new Lists(1);

    l.add(2);
    l.add(3);
    l.add(4);
    l.add(5);



    system("pause");
    return 0;
        }

but it produces an error that says “invalid conversion from List* to int”. Is my using of outside class right? Im a little confused how I will solve this.

#include <cstdlib>
#include <iostream>

using namespace std;

struct Node{
       int data;
       Node *next;       
       Node(int i){
                data = i;
                next = NULL;
                }

       };

class List{
      Node *head;



      public:
      List(int i){
               head = new Node(i);
      }

      void addToHead(int i){
          Node *temp = new Node(i);
          temp->next = head;
          head = temp;
           }

      void add(int i){
                Node *currNode = head;
                while(currNode!= NULL){
                        if(currNode->next == NULL){
                          currNode->next = new Node(i);
                          break;         
                                }
                         else{
                          currNode = currNode-> next;      
                              }   
                                 }

                }
      void deleteNode(int i){
           Node *currNode = head;
           Node *prevNode = NULL;

           while(currNode!=  NULL){
                             if(currNode->data == i) {
                             if(prevNode== NULL){
                                           head = head->next;
                                           }                  
                              else{
                                   prevNode->next = currNode->next;
                                   }                                
                              }
                              prevNode = currNode;
                              currNode =  currNode -> next;                            
                             }
           }
      void insert(int position, Node *n){
           Node *currNode= head;
           Node *prevNode = NULL;

           for(int counter = 0; counter>= position && currNode!= NULL; counter++){
                   if(counter==position){
                              Node *temp = currNode;
                              n->next  =  currNode;
                              prevNode->next= n;                              
                              }                  
                   prevNode = currNode;
                   currNode = currNode-> next;
                   }
           }
      void traverse(Node *node){
           if(node!=NULL){
           cout<<  node-> data  <<endl;
           traverse(node->next);
                          }
           }

      };

Answer 1

Lists l = new Lists(1);

should be:

Lists *l = new Lists(1);

new provides a pointer.

The reason you get that specific error is that the line would be valid if the conversion chain Lists * -> int -> Lists were valid. The second is valid here because of the constructor but the first is not.