[Help] cos() function with Classes

[Max_Payne]

Code:

NumeroReal.h

#pragma once

#include <iostream>
#include <cmath>
#include <cstdlib>

using namespace std;

class NumeroReal
{
private:
	double n;

public:
	NumeroReal();													  // default constructor
	NumeroReal( double n );									   // parameter constructor
	NumeroReal( const NumeroReal &unNumeroReal ); // copy constructor
	~NumeroReal();												   // destructor
 
	void setNumeroReal( double n );
	double getNumeroReal() const;

	friend ostream &operator << ( ostream &output, const NumeroReal &unNumeroReal );
	friend istream &operator >> ( istream &input, NumeroReal &unNumeroReal );

	NumeroReal cos() const;

};

NumeroReal.cpp

#include "NumeroReal.h"

NumeroReal::NumeroReal(void)
{
	this->n = 1.0;
}

NumeroReal::NumeroReal( double n ) 
{
	this->n = n;
}

NumeroReal::NumeroReal( const NumeroReal &unNumeroReal )
{
	this->n = unNumeroReal.n;
}

NumeroReal::~NumeroReal(void)
{
}

//xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx


void NumeroReal::setNumeroReal( double n )
{
	this->n = n;
}

double NumeroReal::getNumeroReal() const
{
	return ( this->n );
}

//xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

ostream &operator << ( ostream &output, const NumeroReal &unNumeroReal )
{
	output << unNumeroReal.n;
	
	return ( output );
}

istream &operator >> ( istream &input, NumeroReal &unNumeroReal )
{
	cout << "Entre un numero real: ";
	cin >> unNumeroReal.n;

	return ( input );
}


NumeroReal NumeroReal::cos() const
{
	return ( this->cos() );
}

Main.cpp

#include "NumeroReal.h"

#include <iostream>
#include <cmath>
#include <conio.h>
#include <cstdlib>

using namespace std;

int main ()
{

	NumeroReal n1, n2( 4.0 );

	cout << "Numero Real # 1" << endl;
	cin >> n1;

	cout << "\nNumero Real # 2" << endl;
	cin >> n2;


	cout << cos( n1 ) << "\n\n";

	system("PAUSE");
		return 0;
}

I want to find the cos( n1 ) but when i try to print it it gives me this error:

------ Build started: Project: CalculosNumeros, Configuration: Debug Win32 ------
Compiling...
Main.cpp
c:\documents and settings\mpayne007\my documents\visual studio 2005\projects\calculosnumeros\calculosnumeros\main.cpp(78) : error C2665: 'cos' : none of the 3 overloads could convert all the argument types
c:\program files\microsoft visual studio 8\vc\include\math.h(116): could be 'double cos(double)'
c:\program files\microsoft visual studio 8\vc\include\math.h(503): or 'float cos(float)'
c:\program files\microsoft visual studio 8\vc\include\math.h(551): or 'long double cos(long double)'
while trying to match the argument list '(NumeroReal)'
Build log was saved at "file://c:\Documents and Settings\MPayne007\My Documents\Visual Studio 2005\Projects\CalculosNumeros\CalculosNumeros\Debug\BuildLog.htm"
CalculosNumeros - 1 error(s), 0 warning(s)
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

[Narue]

>cos( n1 )
n1 is an object of NumeroReal, but it doesn't support an implicit conversion to any of the types that cos expects. Perhaps you meant n1.cos() ? That should give you an interesting result too, but it's more likely to take you in the right direction than trying to convert an object to floating-point. :icon_rolleyes:

[Max_Payne]

I was trying to do an overloading to cos() to be able to use it without the dot.

[Narue]

>I was trying to do an overloading to cos() to be able to use it without the dot.
You never defined a global cos function, so naturally your compiler will find the ones from cmath. Anyway, naming your global functions the same as a standard library function is flirting with danger. I'd suggest you over it and use the dot syntax.

[Max_Payne]

Ok..
Thanks 4 your help...