oveloading operators

[Arnaldo]

Hello, I am trying to do the following:

....
int x;
clsIMG a;
a(10,40) = 40;
x = a(10,40);
.....

the source for my class:

class clsIMG
{
private:
UINT8 img[680][500];
public:
clsIMG(void);
~clsIMG(void);
UINT8 operator()(UINT8 x, UINT8 y);
};

UINT8 clsIMG::operator()(UINT8 x, UINT8 y)
{
return img[x][y];
}

The x = a(10,40) is ok! No problem, how I can do the
a(10,50) = 50;

Thanks
Arnaldo Giacomitti Junior.

[Artie Gold]

Arnaldo wrote:

Hello, I am trying to do the following:

...
int x;
clsIMG a;
a(10,40) = 40;
x = a(10,40);
....

the source for my class:

class clsIMG
{
private:
UINT8 img[680][500];
public:
clsIMG(void);
~clsIMG(void);
UINT8 operator()(UINT8 x, UINT8 y);
};

UINT8 clsIMG::operator()(UINT8 x, UINT8 y)
{
return img[x][y];
}

The x = a(10,40) is ok! No problem, how I can do the
a(10,50) = 50;

Instead of returning a *value* from operator(), return a *reference*.
(Look it up in whatever text you're using for your C++ explorations.)

HTH,
--ag

--
Artie Gold -- Austin, Texas
http://goldsays.blogspot.com (new post 8/5)
http://www.cafepress.com/goldsays
"If you have nothing to hide, you're not trying!"

[John Carson]

"Arnaldo" <gi********@gmail.com> wrote in message
news:11*********************@z14g2000cwz.googlegro ups.com

Hello, I am trying to do the following:

...
int x;
clsIMG a;
a(10,40) = 40;
x = a(10,40);
....

the source for my class:

class clsIMG
{
private:
UINT8 img[680][500];
public:
clsIMG(void);
~clsIMG(void);
UINT8 operator()(UINT8 x, UINT8 y);
Make this one const, i.e.,

UINT8 operator()(UINT8 x, UINT8 y) const;

and declare a new non-const one returning a reference

UINT8 & operator()(UINT8 x, UINT8 y);
};

UINT8 clsIMG::operator()(UINT8 x, UINT8 y)
Change this to

UINT8 clsIMG::operator()(UINT8 x, UINT8 y) const
{
return img[x][y];
}
and define the second operator:

UINT8 & clsIMG::operator()(UINT8 x, UINT8 y)
{
return img[x][y];
}

The x = a(10,40) is ok! No problem, how I can do the
a(10,50) = 50;

--
John Carson