Code

 Header...
#define NX 8
#define NY 6
void setup (int nx,int ny,char image[NY][NX]);

 int floodfill(int x,int y,char image[NY][NX],char area_id,int depth){
   ... 

»  int count;
»  if (x<0||x>=NX||y<0||y>=NY||image[y]x!='*') {
»    return 0;
  }

  // When finished debugging do NOT remove this line, change it to area id
»  »image[y]x='0'+(depth%10);// Was area id

»  count=1+floodfill(x, y-1, image, area_id, depth+1)
     +floodfill(x+1, y-1, image, area_id, depth+1)
     +floodfill(x+1, y, image, area_id, depth+1)
     +floodfill(x+1, y+1, image, area_id, depth+1)
     +floodfill(x, y+1, image, area_id, depth+1)
     +floodfill(x-1, y+1, image, area_id, depth+1)
     +floodfill(x-1, y, image, area_id, depth+1)
     +floodfill(x-1, y-1, image, area_id, depth+1);
  
»  »image[y]x=area_id;
»  return count;
}

#define IMAX 26
 int main(){
   ... 

»  char image[NY][NX];
»  int found=0;
»  int ix, iy, nf;
»  char letters[32]="ABCDEFGHIJKLMNOPQRSTUVWXYZ";
»  int sizes[IMAX];
»  »setup(NX, NY, image);
»  
»  for (iy=0; iy<NY; ++iy) 
    for (ix=0; ix<NX; ++ix) {
»      nf=floodfill(ix, iy, image, lettersfound, 0);
»      if (nf) {
»  sizesfound=nf;
»  ++found;
  }
}
  
»  printf("I found %d islands\n", found);
»  for (ix=0; ix<found; ++ix) 
    printf("Island %c size %d\n", lettersix, sizesix);
»  return 0;
}