Boundary Fill Algorithm in C.c

#include<stdio.h>
#include<graphics.h>
void boundary_fill(int x,int y,int boundary_color,int fill_color);
int main()
{
	int gd,gm,x,y,x1,x2,y1,y2;
	detectgraph(&gd,&gm);
	initgraph(&gd,&gm,"C://TurboC3//BGI");
	
	printf("Enter top-left point of rectangle: ");
	scanf("%d%d",&x1,&y1);
	printf("Enter bottom-right point of rectangle: ");
	scanf("%d%d",&x2,&y2);
	
	cleardevice();
	setcolor(WHITE);
	rectangle(x1,y1,x2,y2);
	boundary_fill(x1+1,y1+1,15,4);
	
	getch();
	closegraph();
	return 0;
}

void boundary_fill(int x,int y,int boundary_color,int fill_color)
{
	int current;
	current=getpixel(x,y);
	if(current!=boundary_color && current!=fill_color)
	{
		putpixel(x,y,fill_color);
		delay(10);
		boundary_fill(x+1,y,boundary_color,fill_color);
		boundary_fill(x,y+1,boundary_color,fill_color);
		boundary_fill(x-1,y,boundary_color,fill_color);
		boundary_fill(x,y-1,boundary_color,fill_color);
	}
}