Flood Fill Function In C Programming 
C Graphics


First approach

#include<stdio.h>
#include<conio.h>
#include<graphics.h>
int main()
{
  int gd=DETECT,gm=1;
  initgraph(&gd,&gm,"c://turboc3//bgi");
  setfillstyle(SOLID_FILL,RED);
  circle(80,303,50);
  floodfill(80,303,WHITE);
  rectangle(100,200,120,220);
  floodfill(110,210,WHITE);
  getch();
  closegraph();
  return 0;
}

Second Approach

#include<graphics.h>
#include<stdio.h>
#include<conio.h>
void flood(int x,int y,int RED,int BLACK)
{
  if(getpixel(x,y)==BLACK)
  {
    putpixel(x,y,RED);
    flood(x+1,y,RED,BLACK);
    flood(x-1,y,RED,BLACK);
    flood(x,y+1,RED,BLACK);
    flood(x,y-1,RED,BLACK);
  }
}

int main()
{
  int gd=DETECT,gm=0,i,j,x1,x,y,y1,x2,y2;
  initgraph(&gd,&gm,"c://turboc3//bgi");
  setcolor(GREEN);
  rectangle(100,200,150,250);
  circle(80,303,50);
  flood(x=120,y=220,RED,BLACK);
  getch();
  closegraph();
  return 0;
}