Re: Multidimensional array member initialization

"io_x" <a@b.c.invalid> ha scritto nel messaggio
news:4b463e69$0$1105$4fafbaef@reader4.news.tin.it...


this is better because all immage is one array without holes

#include <iostream>
#include <stdlib.h>
#define S sizeof
#define R return

using namespace std;

struct Color3d{
    float r, g, b;
};

class Image{
public:
  int height;
  int width;
  char* pxs;

  Image(int height, int width);
  ~Image();
  Color3d& v(int h, int w);
  void fill(Color3d& color);
};

Color3d& Image::v(int h, int w)
{R (Color3d&) *(pxs+w*S(Color3d)+h*width*S(Color3d));}

Image::Image(int h, int w)
{int i, g;

 height=0; width=0; pxs=0;
 if(w<=0||h<=0) return;
 g =h*sizeof(Color3d);
 if(g<=0) return;
 g*=w;
 if(g<=0) return;
 pxs=(char*) malloc(g);
 if(pxs==0) return;
 width=w; height=h;
}

Image::~Image(){free(pxs);}

void Image::fill(Color3d& color)
{int x, y;
 if(pxs==0) return;
 for(x=0; x<height; ++x)
    {for(y=0; y<width; ++y)
             (*this).v(x,y)=color;
    }
}

int main(void)
{Color3d h={0.78373, 0.1383, 1-0.78373-0.1383};
 Image g(768, 1024);
 cout << "Inizio\n";
 if(g.pxs==0)
    {cout << "Error\n"; return 0;}
 g.fill(h);
 cout << "(r,g,b)==(" << g.v(0,0).r << ", "
                      << g.v(0,0).g << ", "
                      << g.v(0,0).b << ")\n";
 cout << "end\n";
 return 0;
}
----------
why is not possible to define:

Color3d& Image::operator[][](int i, int j)
{return (Color3d&) *(pxs+j*sizeof(Color3d)+i*sizeof(Color3d)*width);}