Class Templates... With Classes?

[dthkai]

Hi everybody!

You know... recently I started a research on Templates, and I found this, but I don't know exactly what it has to do, it is part of a test I'm going to do for school

The only advice that was given to me:

"What are the conditions in order for this code to work"

I'm assuming that it has to add the values from cVector3df in a new object created from a template.

What topics should I research in order to learn about this weird Class Templates?

#include "stdafx.h"
#include <cstdlib>
#include <iostream>
using namespace std;

template <class T>
class ClasaTeste
{
private:
	T m_var;
public:
	void Add(T newVar)
	{
        m_var += newVar;
	}

	void Addl(T newVar)
	{
	m_var = m_var + newVar;
	}


};


class cVector3df
{
	float x,y,z;
};

int _tmain(int argc, _TCHAR* argv[])
{
	ClasaTeste<cVector3df> t;
	cVector3df p;
	t.Add(p);
	t.Addl(p);
	system("PAUSE");
	return 0;
}

[Stewbond]

You just need to add operator overloading to class cVector3df like so:

class cVector3df
{
	float x,y,z;
public:
	cVector3df& operator+ (const cVector3df& rhs)
	{
		cVector3df out;
		out.x = x + rhs.x;
		out.y = y + rhs.y;
		out.z = z + rhs.z;
		return out;
	}
	void operator+= (const cVector3df& rhs)
	{
		x += rhs.x;
		y += rhs.y;
		z += rhs.z;
	}
};

[dthkai]

It does work now, but it says that i'm using the variable "p" without being initalized.

I'm researching about operator overloading.

cVector3df& operator+ (const cVector3df& rhs)

is our constructor? how does it come to overload? why?

can we make a constructor for cVector3df, giving our variables a default value and having our operator overloaded?

I'm kinda confused...

[dthkai]

Here's the code again, but I'm not sure about Template Specialization (see code below)

If i'm having <class T> , how can I make a constructor so it takes "R" float, int, or anything else as a template?

#include "stdafx.h"
#include <cstdlib>
#include <iostream>
using namespace std;

template <class T>
class ClasaTeste
{
private:
	T m_var;
public:
	
	//ClasaTeste(){} <- how can I make a constructor here
        //so I can initialize its variables? 
	//I mean, how can I do a Template specialization here?,
        //if I do already have "<class T>"
	
	void Add(T newVar)
	{
m_var += newVar;
	}

	void Addl(T newVar)
	{
	m_var = m_var + newVar;
	}


};


class cVector3df
{
	float x,y,z;
public:

	cVector3df(){}
	cVector3df(float numX, float numY, float numZ)
	{
		x = numX;
		y = numY;
		z = numZ;
	}

	cVector3df& operator+ (const cVector3df& rhs)
	{
		cVector3df out;
		out.x = x + rhs.x;
		out.y = y + rhs.y;
		out.z = z + rhs.z;
		return out;
	}
	void operator += (const cVector3df& rhs)
	{
		x += rhs.x;
		y += rhs.y;
		z += rhs.z;
	}
};

int _tmain(int argc, _TCHAR* argv[])
{
	ClasaTeste<cVector3df> t;
	
	cVector3df p(1,2,3);
   t.Add(p);
	t.Addl(p);
	
	system("PAUSE");
	return 0;
}

[ne555]

cVector3df& operator+ (const cVector3df& rhs)
Warning: returning reference to local variable.

how can I make a constructor so it takes "R" float, int, or anything else as a template?

You put float, int, or anything else between the <>.
Maybe I didn't understand your question, ¿could you exemplify?