Re: Can we override [][] ?
"Mike Wahler" <mkwahler@mkwahler.net> wrote in message
news:5I5fg.9653$y4.1299@newsread2.news.pas.earthlink.net...
"Jim Langston" <tazmaster@rocketmail.com> wrote in message
news:KB5fg.137$212.111@fe04.lga...
I wanted to do an operator override for [][] but couldnt' figure out the
syntax. I tried this (code that doesn't compile commented out with //:
class CMyBitmap
{
public:
CMyBitmap( int Rows, int Columns ): Rows_( Rows ), Columns_( Columns )
{
Data_ = new SPixel[ Rows * Columns ];
}
~CMyBitmap()
{
delete[] Data_;
}
// error C2804: binary 'operator [' has too many parameters
// SPixel& operator[]( const int Row, const int Column )
// {
// return Data_[ Columns_ * Row + Column ];
// }
// error C2092: '[]' array element type cannot be function
// SPixel& operator[][]( const int Row, const int Column )
SPixel& Pixel( const int Row, const int Column )
{
return Data_[ Columns_ * Row + Column ];
}
private:
SPixel* Data_;
int Rows_;
int Columns_;
// No copy or assignment yet so disable by making private.
CMyBitmap ( CMyBitmap const& ) {};
CMyBitmap& operator=( CMyBitmap const& ) {};
};
Can we override 2d array access?
Certainly. But...
[][] is not an operator, it's two instances of the single
operator []. If you have your operator[] do the 'right
thing', you shouldn't have any problems using expressions
such as x[], x[][], x[][][], etc. Post back if you need
more help or an example.
I had goggled for operator[] but goggle doesn't seem to index special
characters (such as '[') so the hits weren't very orderly and it took me a
long time to even find the syntax for [] My manual didn't give me any
examples, time to get a new manual.
I would need an example please, as I don't know how to override[] to accept
two paramters but you seem to indicate it is two instances of []. What is
the 'right thing' or can you direct me to a web page on the subject? As I
said, in this case Google was not my friend.