我们可以覆盖[] []吗？ [英] Can we override [][] ?
问题描述
我想为[] []执行操作符覆盖，但无法找出
语法。我试过这个（没有编译的代码// //
类CMyBitmap
{
public：
CMyBitmap（int Rows，int Columns）：Rows_（Rows），Columns_（Columns）
{
Data_ = new SPixel [Rows *专栏];
}
~CMyBitmap（）
{
delete [] Data_;
}
//错误C2804：二进制''运算符[''参数太多
// SPixel& operator []（const int Row，const int Column）
// {
//返回Data_ [Columns_ * Row + Column];
//}
//错误C2092：''[]''数组元素类型不能是函数
// SPixel& operator [] []（const int Row， const int Column）
SPixel& Pixel（const int Row，const int Column）
{
返回Data_ [Columns_ *行+列];
}
私人：
SPixel * Data_;
int Rows_;
int Columns_;
//没有副本或作业，所以禁用私有。
CMyBitmap（CMyBitmap const& ）{};
CMyBitmap& operator =（CMyBitmap const&）{};
};
我们可以覆盖2d数组访问吗？
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?
推荐答案
" Jim Langston" < TA ******* @ rocketmail.com>在消息中写道
新闻：KB *************** @ fe04.lga ...
"Jim Langston" <ta*******@rocketmail.com> wrote in message
news:KB***************@fe04.lga...
我想做一个算子覆盖[] []，但无法弄清楚
语法。我尝试了这个（没有编译的代码// //
类CMyBitmap
公开：
CMyBitmap（int Rows，int Columns） ：Rows_（Rows），Columns_（Columns）
{
Data_ = new SPixel [Rows * Columns];
}
~CMyBitmap（）
{
删除[] Data_;
}
//错误C2804：二进制''运算符[''参数太多
// SPixel& operator []（const int Row ，const int Column）
// {
//返回Data_ [Columns_ * Row + Column];
//}
//错误C2092：'' []''数组元素类型不能是函数
// SPixel& operator [] []（const int Row，const int Column）
SPixel& Pixel（const int Row，const int专栏）
{
返回Data_ [Columns_ * Row + Column];
}
私人：
SPixel * Data_;
int Rows_ ;
int Columns_;
//没有副本或赋值然后通过私密禁用。
CMyBitmap（CMyBitmap const& ）{};
CMyBitmap& operator =（CMyBitmap const&）{};
};
我们可以覆盖2d数组访问吗？
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?
当然可以。但是......
[] []不是运算符，它是单个
运算符[]的两个实例。如果你有你的算子[]做''
''，你就不会有任何问题使用表达式
如x []，x [ ] []，x [] [] []，等等。如果你需要回复
更多的帮助或一个例子。
-Mike
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.
-Mike
" Mike Wahler" < MK ****** @ mkwahler.net>在消息中写道
新闻：5I **************** @ newsread2.news.pas.earthli nk.net ...
"Mike Wahler" <mk******@mkwahler.net> wrote in message
news:5I****************@newsread2.news.pas.earthli nk.net...
Jim Langston < TA ******* @ rocketmail.com>在消息中写道
新闻：KB *************** @ fe04.lga ...
"Jim Langston" <ta*******@rocketmail.com> wrote in message
news:KB***************@fe04.lga...
我想为[]做一个操作符覆盖[]但无法弄清楚
语法。我尝试了这个（没有编译的代码// //
类CMyBitmap
公开：
CMyBitmap（int Rows，int Columns） ：Rows_（Rows），Columns_（Columns）
{
Data_ = new SPixel [Rows * Columns];
}
~CMyBitmap（）
{
删除[] Data_;
}
//错误C2804：二进制''运算符[''参数太多
// SPixel& operator []（const int Row ，const int Column）
// {
//返回Data_ [Columns_ * Row + Column];
//}
//错误C2092：'' []''数组元素类型不能是函数
// SPixel& operator [] []（const int Row，const int Column）
SPixel& Pixel（const int Row，const int专栏）
{
返回Data_ [Columns_ * Row + Column];
}
私人：
SPixel * Data_;
int Rows_ ;
int Columns_;
//没有副本或赋值然后通过私密禁用。
CMyBitmap（CMyBitmap const& ）{};
CMyBitmap& operator =（CMyBitmap const&）{};
};
我们可以覆盖二维数组访问吗？
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?
当然可以。但是......
[] []不是运算符，它是单个
运算符[]的两个实例。如果你有你的算子[]做正确的事情，你就不应该使用表达式等问题，例如x []，x [] []，x [] [ ] []等等。如果你需要更多的帮助或示例，请回复。
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.
我为操作员[]护目镜但是护目镜没有似乎索引特殊的
字符（例如''[''）因此命中率不是很有序而且我花了很长时间才能找到它[]我的手册的语法没有给我任何
的例子，是时候得到一本新的手册。
我需要一个例子，如同我不知道如何覆盖[]接受
两个参数，但你似乎表明它是[]的两个实例。什么是
''正确的事情''或者你能指导我到这个主题的网页吗？正如我所说，在这种情况下，谷歌不是我的朋友。
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.
Jim Langston发布：
Jim Langston posted:
我需要一个例子，因为我不知道如何覆盖[]来接受两个参数，但你似乎表明它是
[]的两个实例。什么是'正确的''或者你能指导我到这个主题的网页吗？正如我所说，在这种情况下，谷歌不是我的朋友。
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.
我只花了十五分钟，所以这绝不是完美的。
未经测试的代码：
class ChessBoard {
public：
class Square {
public：
enum SquareContents {
空，典当，城堡，马，主教，女王，国王}内容;
Square& operator =（SquareContents const sc）
{
contents = sc;
return * this;
}
};
方形正方形[64];
类HorizontalCoordinate {
私人：
ChessBoard& cb;
unsigned const x;
public：
HorizontalCoordinate（ChessBoard& arg_cb，unsigned const arg_x）
：cb（arg_cb），x（arg_x）{}
Square&运算符[]（无符号常数）
{
返回cb.squares [x * 8 + y];
}
};
HorizontalCoordinate operator []（unsigned const x）
{
返回HorizontalCoordinate（* this，x）;
}
};
int main（）
{
ChessBoard board;
board [3] [5] = ChessBoard :: Square :: bishop;
}
如你所见，一个简单的成员功能（甚至功能风格
运营商）可能会更好。
-Tomás
I only spent fifteen minutes on this, so it''s by no means perfect.
Untested code:
class ChessBoard {
public:
class Square {
public:
enum SquareContents {
empty, pawn, castle, horse, bishop, queen, king } contents;
Square &operator=( SquareContents const sc )
{
contents = sc;
return *this;
}
};
Square squares[64];
class HorizontalCoordinate {
private:
ChessBoard &cb;
unsigned const x;
public:
HorizontalCoordinate(ChessBoard &arg_cb, unsigned const arg_x)
: cb(arg_cb), x(arg_x) {}
Square &operator[]( unsigned const y )
{
return cb.squares[ x * 8 + y ];
}
};
HorizontalCoordinate operator[](unsigned const x)
{
return HorizontalCoordinate(*this, x);
}
};
int main()
{
ChessBoard board;
board[3][5] = ChessBoard::Square::bishop;
}
As you can see, a simple member function (or even function-style
operator) would probably be better.
-Tomás
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