oop-info hiding

my program:

Code:

BOX.H
--------------------
#ifndef BOX_H
#define BOX_H

class Box
{
	private:
		int length;
		int width;

	public:
		//constructor
		Box();

		//methods
		void setValue(int length,int width);
		int getArea();

		//destructor
		~Box();
};

#endif
------------------------
************************


BOX.cpp
------------------------
#include "box.h"

//constructor
Box::Box()
{
	length = 8;
	width = 8;
}

//setter
void Box::setValue(int length,int width)
{
	Box::length = length;
	Box::width = width;
}

//getter
int Box::getArea()
{
	return (Box::length * Box::width);
}

//destructor
Box::~Box()
{
	length = 0;
	width = 0;
}
----------------------------
****************************


BoxMain.cpp
----------------------------
#include <iostream>
#include "box.h"

int main()
{
	Box small, medium, large;

	small.setValue(5,7);

	large.setValue(15,20);

	//display results
	std::cout << "\nThe small box area is " << small.getArea();
	std::cout << "\nThe medium box area is " << medium.getArea();
	std::cout << "\nThe large box area is " << large.getArea() << std::endl;

	return 0;
}
-----------------------------
*****************************

My question:

As you can see in the methods, i have declared the variables inside the setter methods same as the private objects in the class.
My aim was to be able to use same name as you can see.
If i DO NOT prefix the private data with Box:: as shown below

Code:

//setter
void Box::setValue(int length,int width)
{
	length = length;
	width = width;
}

i DO NOT get the desired output since the compiler is confused.

But if i prefix the private data with the Box:: as shown below:

Code:

//setter
void Box::setValue(int length,int width)
{
	Box::length = length;
	Boxx::width = width;
}

the program works fine!

So, i want to ask if the way i did is correct or not???

Thanks for ur attention!

Kind Regards,
wakish

Never knew that it worked your way too.
The usual way is

Code:

void Box::setValue(int length,int width)
{
	this->length = length;
	this->width = width;
}

Kurt

yeah..in java we have this:

this.lenght=length;
this.width=width;

return this.lenght;

etc...

but is it similar in C++??


And btw "this->variable" is same as "this.variable", right??

Try it. In c++ there is no this.length. In c++ this is a pointer.
Kurt

From what I've seen, another way would be to adopt some naming convention for member variables, e.g. a trailing underscore. You would then be able to do this:

Code:

void Box::setValue(int length, int width)
{
    length_ = length;
    width_ = width;
}

And btw "this->variable" is same as "this.variable", right??

"this->variable" is the same as "(*this).variable".