Templates

[Puvendran]

Hi,

I am writing a simple program to use templates. Basically the program
should be able create a stack of any type with ultimately 2 methods
one to add (push) and one to remove (pop) from the stack.

I am getting a compilation error thus - it's the stack<int>
s(10)declaration which seems to be the problem


Undefined first referenced
symbol in file
stack<int>::stack(int) /var/tmp/ccdiGgf1.o
ld: fatal: Symbol referencing errors. No output written to p
collect2: ld returned 1 exit status

Programs involved :


The main prog is

#include "p_stack.h"
//#include <iostream.h>

void
main()
{
stack<int> s(10);

int i;

for (int j=0;j < 12; j++)
{
//s.push(j);

}

for (int j=0;j < 10; j++)
{
//cout << s.pop() << endl;
}

}

The "p_stack.h" is

#include <vector>

template<class T>
class stack
{
public :

//int max_size;
//int curr_size;
vector<T> v;

stack(int);

//void push(T);
//T pop();
};

p_stack.cc is

#include "p_stack.h"
#include <string>

template<class T>
stack<T>::stack(int i)
{
v.resize(i);
}


I thank you in advance for any assistance.

Puvendran

 

[DarkSpy]

5 Nov 2003 22:54:18 -0800 (e-mail address removed)
(Puvendran)

Hi,

I am writing a simple program to use templates. Basically the program
should be able create a stack of any type with ultimately 2 methods
one to add (push) and one to remove (pop) from the stack.

I am getting a compilation error thus - it's the stack<int>
s(10)declaration which seems to be the problem


Undefined first referenced
symbol in file
stack<int>::stack(int) /var/tmp/ccdiGgf1.o
ld: fatal: Symbol referencing errors. No output written to p
collect2: ld returned 1 exit status

Programs involved :


The main prog is

#include "p_stack.h"
//#include <iostream.h>

void
main()
{
stack<int> s(10);

int i;

for (int j=0;j < 12; j++)
{
//s.push(j);

}

for (int j=0;j < 10; j++)
{
//cout << s.pop() << endl;
}

}

C++ standard:
int main() or main() will return a int value implicit.

The "p_stack.h" is

#include <vector>

template<class T>
class stack
{
public :

//int max_size;
//int curr_size;
vector<T> v;

that is std::vector<T>
or define
using namespace std;
or define
using std::vector

to tell compiler the vector is defined with namespace std.

stack(int);

//void push(T);
//T pop();
};

p_stack.cc is

#include "p_stack.h"
#include <string>

template<class T>
stack<T>::stack(int i)
{
v.resize(i);
}


I thank you in advance for any assistance.

Puvendran

[comp.lang.c++]
[comp.lang.c++.moderated]
DarkSpy, A C++ Mad Dog.

 

[Oplec]

Hi,

I am writing a simple program to use templates. Basically the program
should be able create a stack of any type with ultimately 2 methods
one to add (push) and one to remove (pop) from the stack.

I am getting a compilation error thus - it's the stack<int>
s(10)declaration which seems to be the problem


Undefined first referenced
symbol in file
stack<int>::stack(int) /var/tmp/ccdiGgf1.o
ld: fatal: Symbol referencing errors. No output written to p
collect2: ld returned 1 exit status

Programs involved :


The main prog is

#include "p_stack.h"
//#include <iostream.h>

void
main()
{
stack<int> s(10);

int i;

for (int j=0;j < 12; j++)
{
//s.push(j);

}

for (int j=0;j < 10; j++)
{
//cout << s.pop() << endl;
}

}

The "p_stack.h" is

#include <vector>

template<class T>
class stack
{
public :

//int max_size;
//int curr_size;
vector<T> v;

stack(int);

//void push(T);
//T pop();
};

p_stack.cc is

#include "p_stack.h"
#include <string>

template<class T>
stack<T>::stack(int i)
{
v.resize(i);
}


I thank you in advance for any assistance.

Puvendran

If your compiler does not support the C++ "export" feature for
templates, and most compilers do not, then you must include you class
template member definitions after your class template definition in
every .cc file that will use your class template. What that means is
that you need to copy the member definition from p_stack.cc to p_stack.h
and make sure that the member definition is placed after the template
definition.

You should have this for p_stack.h

#ifndef P_STACK_H
#define P_STACK_H

#include <vector>

template<class T>
class stack
{
public :

//int max_size;
//int curr_size;
vector<T> v;

stack(int);

//void push(T);
//T pop();
};

template<class T>
stack<T>::stack(int i)
{
v.resize(i);
}

#endif // #ifndef P_STACK_H

 

[Gavin Deane]

Hi,

I am writing a simple program to use templates. Basically the program
should be able create a stack of any type with ultimately 2 methods
one to add (push) and one to remove (pop) from the stack.

I am getting a compilation error thus - it's the stack<int>
s(10)declaration which seems to be the problem


Undefined first referenced
symbol in file
stack<int>::stack(int) /var/tmp/ccdiGgf1.o
ld: fatal: Symbol referencing errors. No output written to p
collect2: ld returned 1 exit status

<code snipped>

See http://www.comeaucomputing.com/techtalk/templates/#whylinkerror

Either use the export keyword when defining the stack constructor if
your compiler supports export, or put #include "p_stack.cc" at the end
of p_stack.h. If you do that, make sure that p_stack.cc _does not_
include p_stack.h.

hth
GJD