Question

following linked list implementation with stacks works fine

#include <iostream>
using namespace std;
   class Link
   {
   public:
       long ddata;
       Link *next;
       Link(long d){
        ddata=d;

       }
        void displaylink(){
         cout<<ddata<<"  "<<endl;

        }



   };
   class LinkedList{
   private :

    Link * first;
   public:
       LinkedList(){
        first=NULL;

       }


       bool empthy(){

        return first==NULL;
       }
       void insertfirst(long dd){
        Link *newlink=new Link(dd);
        newlink->next=first;
        first=newlink;

       }
       long deletefirst(){

        Link *temp=first;
        first=first->next;
        return temp->ddata;


       }
        void display(){

         Link *current=first;
         while(current!=NULL){
             current->displaylink();
             current=current->next;

         }

          cout<<endl;
        }


   };



   class StackList{
   public:
     LinkedList *ls;
   public:
       StackList(){
           ls=new LinkedList();

       }
         void push(long j){
             ls->insertfirst(j);

         }
            long pop(){
                return   ls->deletefirst();

            }

            bool empthy()
            {
                return (ls->empthy());
            }
                void displaystack(){
                    ls->display();


                }



   };
int main(){


     StackList *SL=new StackList();
     SL->push(20);
     SL->push(40);
     SL->push(60);
     SL->displaystack();
     SL->pop();
     SL->displaystack();


 return 0;
}

but i am interested if it has some possible bugs or can it be optimized more?if you see some nonsecury point in this code please tell me how to correct it?thanks a lot,it is just curiosity question

Answer 1

Your memory management is flawed – as is, it will leak because there are news but no deletes. Once you take care of the deletes, make sure you handle copies of the classes (have the rule of three in mind).