Thread: Please help with C++ templates - going through the tutorials

Hello guys.

A couple of quick questions. First one, I'd rather not post using my real name, but if I login without Facebook, I can't start a thread. What's the secret?

Secondly, I'm a PHP and JavaScript programmer (experienced with OO), I'm just going through the nice C++ tutorials on this site and doing some experimentation.

I've got to the Templates tutorial:

Template Classes in C++ - Cprogramming.com

But now I'm stuck. I even copied and pasted the code snippets provided from that tutorial into my files, and the compiler still complains. The output I'm getting is this (it's a similar error if I just copy & paste the snippets, but below is "my own" version of the code).

I'm using Code::Blocks and the default compiler setup that comes with that IDE.

Code:

obj\Debug\main.o||In function `main':|
C:\stuff\vics\experiment\TemplateExperiment\TemplateExperiment\main.cpp|11|undefined reference to `Multiplier<int>::multiply(int, int)'|
||=== Build finished: 1 errors, 0 warnings ===|

Below are the three files I'm using:

main.cpp:

Code:

include <iostream>
#include "Multiplier.h"


using namespace std;


int main()
{
    int num1 = 5;
    int num2 = 10;
    Multiplier <int> multiplier;
    int result = multiplier.multiply( num1, num2 );
    cout << result << "\n\n";
}

Multiplier.h

Code:

#ifndef MULTIPLIER_H
#define MULTIPLIER_H




template <class Type> class Multiplier
{
    public:
        Type multiply(Type firstNumber, Type secondNumber);
    protected:
    private:
};


#endif // MULTIPLIER_H

Multiplier.cpp

Code:

#include "Multiplier.h"


/*
Multiplier::Multiplier()
{
    // Constructor
}




template <class Type> Type Multiplier<Type>::Multiplier()
{
    // Constructor
}
*/


template <class Type> Type Multiplier<Type>::multiply( Type firstNumber, Type secondNumber)
{
    return firstNumber * secondNumber;
}