class - C++: Copy constructor is deleting nodes in original object -

i have implemented singly linked list using template class , attempted create working copy constructor. when copy constructor called, accurately duplicates list. however, deletes nodes original.

here class implementation, constructors, , destructors:

template<class l> class linkedlist { public:         linkedlist();         linkedlist(const linkedlist<l> &og);         ~linkedlist();          node<l>* addtoend(l object);         node<l>* addtomiddle(l object);         node<l>* deletenode(l deleteitem);         node<l>* reverselist();         void display();         int size();  private:         node<l>* head;         node<l>* tail;         int size; };  template<class l> linkedlist<l>::linkedlist() {         head = null;         tail = null;         size = 0; }  template<class l> linkedlist<l>::linkedlist(const linkedlist<l> &og) {     cout << "\ncopy constructor has been called.\n\n";     head = new node<l>;     *head = *og.head;      tail = new node<l>;     *tail = *og.tail;      size = og.size; }  template<class l> linkedlist<l>::~linkedlist() {     delete head;     delete tail; } 

and main.cpp:

#include "header.h"  int main() {         int int1 = 1;         int int2 = 2;         int int3 = 3;         int int4 = 4;         int int5 = 5;          cout << "creating first integer list..." << endl;          linkedlist<int> intlist1;          intlist1.addtoend(int1);         intlist1.addtoend(int2);         intlist1.addtoend(int3);         intlist1.addtoend(int4);         intlist1.addtoend(int5);          intlist1.display();          cout << endl << "cloning , reversing..." << endl;          linkedlist<int> intlist2(intlist1);         intlist2.reverselist();          cout << "original list: " << endl;          intlist1.display();          cout << "reversed list: " << endl;          intlist2.display();          return 0; } 

the output looks this:

creating first integer list... 1 2 3 4 5

cloning , reversing...

copy constructor has been called.

original list: 1 2 1 reversed list: 5 4 3 2 1

your copy constructor totally wrong. should iterate through linked list , copy each element of list. tail should point last element of list. code this.

template<class l> linkedlist<l>::linkedlist(const linkedlist<l> &og) {     cout << "\ncopy constructor has been called.\n\n";     head = new node<l>;     *head = *og.head;      node *p  = og.head->next;     node *i = head;     while (p != null) {         i->next = new node<l>;         *(i->next) = *p;         p = p->next;         = i->next;     }      tail = i;     size = og.size; }