c++ - InsertNode function shutting down program -

i having trouble coding linked list template. compiles these errors:

1>main.obj : error lnk2019: unresolved external symbol "public: __thiscall linkedlist::~linkedlist(void)" (??1?$linkedlist@h@@qae@xz) referenced in function _main

1>main.obj : error lnk2019: unresolved external symbol "public: void __thiscall linkedlist::deletenode(int)" (?deletenode@?$linkedlist@h@@qaexh@z) referenced in function _main

1>main.obj : error lnk2019: unresolved external symbol "public: void __thiscall linkedlist::displaylist(void)" (?displaylist@?$linkedlist@h@@qaexxz) referenced in function _main

1>main.obj : error lnk2019: unresolved external symbol "public: void __thiscall linkedlist::insertnode(int)" (?insertnode@?$linkedlist@h@@qaexh@z) referenced in function _main

1>c:\users\pr0hz\documents\visual studio 2010\projects\listtemplate\debug\listtemplate.exe : fatal error lnk1120: 4 unresolved externals

any appreciate have been staring @ screen past couple of hours trying solve problem. here code:

main.cpp

#include <iostream> #include <conio.h> #include "linkedlist.h"  using namespace std;   int main() {    linkedlist<int> list;  list.insertnode(5); list.insertnode(7); list.insertnode(1); list.insertnode(19); list.insertnode(16); list.insertnode(22);  cout << "\ndisplay list: \n"; list.displaylist(); cout << endl;  list.deletenode(16);  cout << "\ndisplay node 16 deleted: \n"; list.displaylist(); cout << endl;  linkedlist<int> list2 = list;  cout << "\ndisplay list 2: \n"; list2.displaylist(); cout << endl; getch();  return 0; } 

linkedlist.h

#ifndef linkedlist_h #define linkedlist_h #include <iostream>  using namespace std;  template <class t> class linkedlist { private: struct listtemplate {     t value;     listtemplate *next; };  listtemplate *head;   public: //constructor linkedlist() { head = null; }  //destructor ~linkedlist();  //copy constructor linkedlist(listtemplate &obj) {     listtemplate *nodeptr = &obj;   //move through list     listtemplate *newnode = new listtemplate;      if(!head)         return;     else     {         newnode = head;          while(nodeptr->next)         {             nodeptr = nodeptr->next;             newnode->next = nodeptr;         }      } }  void appendnode(t); void insertnode(t); void deletenode(t); void displaylist(); }; #endif 

linkedlist.cpp

#include "linkedlist.h" #include <iostream>  using namespace std;  template <class t> void linkedlist<t>::appendnode(t newvalue) { listtemplate *newnode;  //point new node listtemplate *nodeptr;  //move through list  //allocate new node , store num there newnode = new listtemplate; newnode->value = num; newnode->next - null;  if(!head)     head = newnode; else {     //initialize nodeptr head move through list     nodeptr = head;      //while there still node, move through until there no more     while (nodeptr->next)         nodeptr = nodeptr->next;      //append node     nodeptr->next = newnode; } }  template <class t> void linkedlist<t>::insertnode(t newvalue) { listtemplate *newnode;              //new node listtemplate *nodeptr;              //move through list listtemplate *previousnode = null;  //the previous node  //allocate new node , store num newnode = new listtemplate; newnode->value = num;  //if no node, new node head if (!head) {     head = newnode;     newnode->next = null; }  else //insert node needs {     nodeptr = head;         //beginning position      previousnode = null;      //skip nodes less newnode     while(nodeptr != null && nodeptr->value < num)     {         previousnode = nodeptr;         nodeptr = nodeptr->next;     }      //if newnode 1st in list, insert in slot 1     if (previousnode == null)     {         head = newnode;         newnode->next = nodeptr;     }     else //insert after previous node     {         previousnode->next = newnode;         newnode->next = nodeptr;     } } }  template <class t> void linkedlist<t>::deletenode(t searchnum) { listtemplate *nodeptr; listtemplate *previousnode;  //if list empty, nothing if(!head)     return;  //see if first node 1 if(head->value == num) {     nodeptr = head->next;     delete head;     head = nodeptr; }  else //find node delete {     nodeptr = head;      //skip nodes not equal num     while (nodeptr != null && nodeptr->value != num)     {         previousnode = nodeptr;         nodeptr = nodeptr->next;     }      //delete node , link previous node 1 of 1 being deleted     if (nodeptr)     {         previousnode->next = nodeptr->next;         delete nodeptr;     } } }  template <class t> linkedlist<t>::~linkedlist() { listtemplate *nodeptr; listtemplate *nextnode;  nodeptr = head;  while (nodeptr != null) {     nextnode = nodeptr->next;      delete nodeptr;      nodeptr = nextnode; } }  template <class t> void linkedlist<t>::displaylist() { listtemplate *nodeptr;  nodeptr = head;  while(nodeptr) {     cout << nodeptr->value << " ";     nodeptr = nodeptr->next; } } 

once again, help!

you shouldn't implementing template functions in source files.
see here - why can templates implemented in header file?

try moving template functions header file (linkedlist.h), , recompile