帮助复制构造函数。 [英] Help With Copy Constructor.
问题描述
我仍然在开发我的游戏，我的程序越来越好了。我希望工作的最多
。我想我在复制
构造函数时遇到了麻烦。基本上我希望它复制gdata数组。如果我这样做，我的gdata
将起作用：gdata [32] = this-> get（lp）;但这不是我想要做的事情。当我编写代码时，我会得到一些神秘的错误。
注释掉了。
49 C：\Documents and Settings \Work\My Documents\C ++ \Dungeon
Adventure2 \gaphic.cpp将`const graphic''作为'this''参数传递
`BYTE graphic :: get（int）''丢弃限定词
C：\Documents and Settings \Work\My Documents\ C ++ \ Dungeon
Adventure2 \ Makefile.win [构建错误] [gaphic.o]错误1
我对指针和对象非常好但是我的编译器很令人沮丧
我。我可以得到一些建议，让这个复制建设者做它所需要的
。
class graphic {
int btmap;
int lr，ud; //图形的Diminsion（大小）
BYTE gdata [32]; //位图数组
HBITMAP hbitmap;
BITMAP位图;
HDC hdc，hdcmem;
void copy（ BYTE in []）;
BYTE get（int n）{return gdata [n];}
public：
graphic（）;
graphic（BYTE c []）;
graphic（const graphic&）;
graphic& operator =（graphic&）;
void SetGr（BYTE c []）;
void set（BYTE c []）;
void显示（HWND，int，int）;
};
graphic :: graphic（const graphic& gr）{
for（int lp = 0; lp！= 32; lp ++）{
// gdata [32] = gr.get（lp）; < - 我收到错误。
}
ud = lr = 16;
BITMAP位图= {0，ud，lr，2， 1,1};
bitmap.bmBits = gdata;
hbitmap = CreateBitmapIndirect（& bitmap）;
}
我正在调用这样的复制构造：
if（play）{
cgr = new graphic（play-> gOut（））;
return * cgr;
}
如果这有帮助
JoeC写道：
BYTE get（int n）{return gdata [n ];}
BYTE get（int n）const {return gdata [n];}
现在Google for ; const correct。你应该不断改变任何方法
不会改变*这个。
-
Phlip
http://c2.com/cgi/wiki?ZeekLand < - - 不是博客!!!
" JoeC" <恩***** @ yahoo.com>在消息中写道
news：11 ********************** @ g10g2000cwb.googlegr oups.com ...我还在继续我的游戏，我的计划越来越好了。大多数我想要的作品。我想我在复制
构造函数时遇到了麻烦。基本上我希望它复制gdata数组。如果我这样做，我的gdata将会起作用：gdata [32] = this-> get（lp）;但这并不是我想要做的事情当我编写代码时，我会得到一些神秘的错误。
它在我看来，最简单，最直接的方式来复制gdata的
内容就是这样做：
graphic :: graphic（const graphic& gr）
{
memcpy（gdata，gr.gdata，sizeof（BYTE）* sizeof（gdata））;
}
- 丹尼斯
I am still working on my game and my program is getting better. Most
of what I want to works. I think I am having trouble with copy
constructor. Basically I want it to copy the gdata array. My gdata
will work if I do: gdata[32] = this->get(lp); But that is not what I
want to do I get some cryptic errors when I write the code like that is
commented out.
49 C:\Documents and Settings\Work\My Documents\C++\Dungeon
Adventure2\gaphic.cpp passing `const graphic'' as `this'' argument of
`BYTE graphic::get(int)'' discards qualifiers
C:\Documents and Settings\Work\My Documents\C++\Dungeon
Adventure2\Makefile.win [Build Error] [gaphic.o] Error 1
I am pretty good with pointer and objects but my compiler is fustrating
me. Can I get some advice to make this copy constructer do what it is
suppoded to do.
class graphic{
int btmap;
int lr,ud; //Diminsion (size) of the graphic
BYTE gdata[32]; //bitmap array
HBITMAP hbitmap;
BITMAP bitmap;
HDC hdc, hdcmem;
void copy(BYTE in[]);
BYTE get(int n){return gdata[n];}
public:
graphic();
graphic(BYTE c[]);
graphic(const graphic&);
graphic& operator = (graphic&);
void SetGr(BYTE c[]);
void set(BYTE c[]);
void display(HWND, int, int);
};
graphic::graphic(const graphic& gr){
for(int lp = 0; lp != 32; lp++){
//gdata[32] = gr.get(lp); <- I get errors.
}
ud = lr = 16;
BITMAP bitmap = {0,ud,lr,2,1,1};
bitmap.bmBits = gdata;
hbitmap = CreateBitmapIndirect(&bitmap);
}
解决方案I am calling the copy constructr like this:
if(play){
cgr = new graphic(play->gOut());
return *cgr;
}
In case this helps
JoeC wrote:
BYTE get(int n){return gdata[n];}
BYTE get(int n) const {return gdata[n];}
Now Google for "const correct". You should make constant any method that
doesn''t change *this.
--
Phlip
http://c2.com/cgi/wiki?ZeekLand <-- NOT a blog!!!
"JoeC" <en*****@yahoo.com> wrote in message
news:11**********************@g10g2000cwb.googlegr oups.com...I am still working on my game and my program is getting better. Most
of what I want to works. I think I am having trouble with copy
constructor. Basically I want it to copy the gdata array. My gdata
will work if I do: gdata[32] = this->get(lp); But that is not what I
want to do I get some cryptic errors when I write the code like that is
commented out.
It seems to me that the easiest and most straight-forward way to copy the
contents of gdata is to simply do this:
graphic::graphic(const graphic& gr)
{
memcpy( gdata, gr.gdata, sizeof(BYTE) * sizeof(gdata) );
}
- Dennis
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