farrooda
asked on
Error LNK2001
I created a class node and try to create an instance of it but it keeps giving me errors;
//node.h
#ifndef NODE_H
#define NODE_H
template<class nodetype>
class node
{
public: nodetype getdata();
node(nodetype=0);
private:nodetype data;
node<nodetype> *nextptr;
};
#endif
--------------------------
//node.cpp
#include"node.h"
template<class nodetype>
nodetype node< nodetype >::getdata()
{ return data;}
template<class nodetype>
node< nodetype >::node(nodetype value)
{
data=value;
nextptr=0;
}
--------------------------
#include<iostream.h>
#include"node.h"
void main()
{
node<int> n(5);
}
--------------------------
Compiling...
node.cpp
Linking...
main.obj : error LNK2001: unresolved external symbol "public: __thiscall node<int>::node<int>(int)"
Debug/assignment1.exe : fatal error LNK1120: 1 unresolved externals
Error executing link.exe.
assignment1.exe - 2 error(s), 0 warning(s)
//node.h
#ifndef NODE_H
#define NODE_H
template<class nodetype>
class node
{
public: nodetype getdata();
node(nodetype=0);
private:nodetype data;
node<nodetype> *nextptr;
};
#endif
--------------------------
//node.cpp
#include"node.h"
template<class nodetype>
nodetype node< nodetype >::getdata()
{ return data;}
template<class nodetype>
node< nodetype >::node(nodetype value)
{
data=value;
nextptr=0;
}
--------------------------
#include<iostream.h>
#include"node.h"
void main()
{
node<int> n(5);
}
--------------------------
Compiling...
node.cpp
Linking...
main.obj : error LNK2001: unresolved external symbol "public: __thiscall node<int>::node<int>(int)"
Debug/assignment1.exe : fatal error LNK1120: 1 unresolved externals
Error executing link.exe.
assignment1.exe - 2 error(s), 0 warning(s)
ASKER
no it didn't work
same error
same error
You don't define a constructor for node<T>. Thus the compiler generates only a default constructor.
-bcl
-bcl
I have tested and didn't have compiler/linker errors.
Oops, my bad. I misread the code.
ASKER
i didn't understand could you explain more plz?
Are you using visual studio?
Just hit Build...Rebuild
usually does the trick to get rid of that error ;)
Hope it helps,
Jens
Just hit Build...Rebuild
usually does the trick to get rid of that error ;)
Hope it helps,
Jens
ASKER
well i am having a linker errors
my compiler is microsoft vc++ 6 service pack 5
should i include something in the project link settings?
my compiler is microsoft vc++ 6 service pack 5
should i include something in the project link settings?
ASKER
same error:(
Maybe your makefile is not correct. I guess your are compiling all files needed but not linking all together.
ASKER CERTIFIED SOLUTION
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
ASKER
the funny think is if i write
node<int> n(5);
or
node<int> n;
I get an error but when I write node<int> n();
I dont get an error
but when i try to do n.getdata();
it gives me an error:
error C2228: left of '.getdata' must have class/struct/union type
node<int> n(5);
or
node<int> n;
I get an error but when I write node<int> n();
I dont get an error
but when i try to do n.getdata();
it gives me an error:
error C2228: left of '.getdata' must have class/struct/union type
I agree, that's why I did not compiler errors, because I was lazy and joined all in one file.
ASKER
thanks mnashadka everything is fine now
farrooda, I think the error with node<int> n(); is because the compiler is interpreting that as a forward declaration for a function n() that returns type node<int>. Then, when you call n.getdata(), it has problems since n is a function.
Anyway, I'm glad that I could help.
Anyway, I'm glad that I could help.
node(nodetype=0);
must be:
node(nodetype value=0);