#include <graphics.h>	
#include <stdlib.h>	
#include <stdio.h>	
#include <conio.h>	
#include <math.h>	
#include <dos.h>	
// this function initializes graphics mode	
// it will work only if you're using Borland C++ compiler & BGI drivers	
// if you're using another compiler you should overwrite body of this function	
void init_gr(void)	
{	
   /* request autodetection */	
   int gdriver = DETECT, gmode, errorcode;	
   /* initialize graphics mode */	
   initgraph(&gdriver, &gmode, "");	
   /* read result of initialization */	
   errorcode = graphresult();	
   if (errorcode != grOk)    /* an error occurred */	
   {	
      printf("Graphics error: %s\n", grapherrormsg(errorcode));	
      printf("Press any key to halt:");	
      getch();	
      exit(1);               /* return with error code */	
   }	
}	
// this function shuts graphics mode down	
// it will work only if you're using Borland C++ compiler & BGI drivers	
// if you're using another compiler you should overwrite body of this function	
void end_gr(void)	
{	
  closegraph();	
}	
// this function set filling style	
// it will work only if you're using Borland C++ compiler & BGI drivers	
// if you're using another compiler you should overwrite body of this function	
void SetFillStyle(int pattern,int color)	
{	
  setfillstyle(pattern,color);	
}	
// this function draws a bar	
// it will work only if you're using Borland C++ compiler & BGI drivers	
// if you're using another compiler you should overwrite body of this function	
void Bar(int x1, int y1, int x2, int y2)	
{	
  bar(x1,y1,x2,y2);	
}	
// this function sets palette entry using RGB color coding	
// it will work only if you're using Borland C++ compiler & BGI drivers	
// if you're using another compiler you should overwrite body of this function	
void SetRGBPalette(int colornum, int red, int green, int blue)	
{	
  setrgbpalette(colornum,red,green,blue);	
}	
// this function reads palette	
// it will work only if you're using Borland C++ compiler & BGI drivers	
// if you're using another compiler you should overwrite body of this function	
void GetPalette(struct palettetype far *palette)	
{	
  getpalette(palette);	
}	
#define N   30 // steps of fading to black	
struct palettetype pal;	
struct {int R;int G;int B;} colors[16];	
int main(void)	
{	
  // initializing graphics mode	
  init_gr();	
  // creating palette	
  GetPalette(&pal);	
  for(int i=0;i<pal.size-1;i++)	
  {	
     colors[i+1].R=0;	
     colors[i+1].G=30-2*i;	
     colors[i+1].B=15+i*2;	
     SetRGBPalette(pal.colors[i+1],colors[i+1].R,colors[i+1].G,colors[i+1].B);	
  }	
  // drawing picture	
  for (i=1;i<16;i++)	
  {	
     SetFillStyle(SOLID_FILL,i);	
     Bar((i-1)*43,0,i*43,479);	
  }	
  // fading to balck	
  for (int j=0;j<N;j++)	
  {	
     //delay(50);	
     for (i=1;i<pal.size;i++)	
        SetRGBPalette(pal.colors[i],	
   colors[i].R*(1-(float)j/N),	
          colors[i].G*(1-(float)j/N),	
          colors[i].B*(1-(float)j/N));	
  }	
  // and back to the light	
  for (j=0;j<N;j++)	
  {	
     //delay(50);	
     for (i=1;i<pal.size;i++)	
        SetRGBPalette(pal.colors[i],	
          colors[i].R*(float)j/N,	
          colors[i].G*(float)j/N,	
          colors[i].B*(float)j/N);	
  }	
  /* clean up */	
  getch();	
  end_gr();	
  return 0;	
}