From:	"Scott Tsai" <scottt AT tpts5 DOT seed DOT net DOT tw>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Problem with C++ & Allegro
Date:	1 Feb 1999 19:29:10 GMT
Organization:	SEEDNet News Service
Lines:	69
Message-ID:	<01be4e19$14d058a0$d1c4af8b@scotttsa>
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To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp
Reply-To:	djgpp AT delorie DOT com

I'm trying to write a very simple class (called Picture)that uses the
Allegro library to display bitmaps.

when I use

Picture pic1 = filename[1];
Picture pic2 = filename[2];
.
.

while(1) {
 pic1.show();
 pic2.show();
}

it's always okay.

but when I do

Picture pics[5];

or

Picture *pics = new Picture[5];

then do

int i = 0;
while(...) {
 i%=5;
 pics[i].show();
 i++;
}

After I call Picture::Picture(char*) the BITMAP *pic in all the
Picture objects (pic[1], pic[2] ....) are always pointed to the
same address(the last picture I load), only the PALLETE pic_pallete
in each object differs, why?

here's my code:

class Picture
{
 private:

  BITMAP* pic;
  PALLETE pic_pallete;

 public:

  Picture() {}   //I don't know how to write a default constructor
                 //for the class

  Picture(char* filename) { pic = load_bitmap(filename, pic_pallete); }

  ~Picture() { destroy_bitmap(pic); }

  void show(void)
  {
   set_pallete(pic_pallete);
   blit(pic, screen, 0, 0, (SCREEN_W - pic->w)/2, (SCREEN_H - pic->h)/2,
pic->w, pic->h);
  }

};


I guess this is a because I didn't learn C++ well enough.....

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