c++ templates implementing on structures -

there wrong c++ code. i've compiled in vc ++ 6.0. it's giving error "cannot deduce template argument type"... problem in display function.

here's code:

#include "stdafx.h" #include <iostream> #include <conio.h> using namespace std;  template <class type>   struct 1 {   type data;   1 *next; };  one<int> *head, *temp, *mid, *del = null;  template <class type> void athead(type value)     {       1 *node = new one;       node->data = value;       node->next = head;       head = node; }  template <class type> void add_at_tail(type value)    {   1 *node = new one;      node->data = value;       node->next = null;    if(head == null)   {     head = node;        temp = head;   }    while(temp->next != null)      {     temp = temp->next;   }    if(temp != node)   {     temp->next = node;     } }  template <class type> void display() {   one<type> *temp = new one;   temp = head;     cout << "\n\n" << endl;      while(temp != null)      {     cout << " " << temp->data << " " << "->";     temp = temp->next;   }   cout << "\n\n\n"; }  int main() {   int a, b, c;   cout << "enter data: " << endl;   cin >> a;   add_at_tail(a);   cout << "enter data: " << endl;   cin >> b;   add_at_tail(b);   cout << "enter data: " << endl;   cin >> c;   add_at_tail(c);    display();    return 0; } 

couple problems here, @ least:

first, have defined template function:

template<class type> void display() {     one<type> *temp=new one;     temp=head;       cout<<"\n\n"<<endl;        while(temp!=null)        {         cout<<" "<<temp->data<<" "<<"->";         temp=temp->next;     }     cout<<"\n\n\n"; } 

this line malformed, because one not complete type (one class template)

one<type> *temp=new one; 

you need this:

one<type> *temp=new one<type>; 

then down in client code, attempt call function template this:

display(); 

but display function template no arguments, there's no way compiler can deduce type of it's template parameter type. must specify type of type @ call point.

display<int>(); 

there logic errors implementation of display(). instantiate single copy of one , don't initialize it. try iterate on it's linked list, it's not -- uninitialized node created. want pass in linked list you're trying iterate over. along these lines:

template<class type> void display(const one<type>& head) {     one<type> const * temp = &head;     cout<<"\n\n"<<endl;        while(temp!=null)        {         cout<<" "<<temp->data<<" "<<"->";         temp=temp->next;     }     cout<<"\n\n\n"; } 

now display takes parameters mentioned in template, compiler able deduce type. want call this:

display(head);