Boundary and Flood Fill

#include <stdio.h>
#include <conio.h>
#include <graphics.h>

void startGraphics(){
    int gd=DETECT, gm;
    initgraph(&gd, &gm, "C:\\TURBOC3\\BGI");
    cleardevice();
}

void fFill(int x, int y, int o, int n){
    if(getpixel(x, y)==o){ //fill until pixel's color matches with old color
        putpixel(x, y, n);

        fFill(x+1, y, o, n);
        fFill(x-1, y, o, n);
        fFill(x, y+1, o, n);
        fFill(x, y-1, o, n);
    }
}

void bFill(int x, int y, int bg, int fg){
    if(getpixel(x, y)!=bg && getpixel(x, y)!=fg){ //fill until boundary's not reached
        putpixel(x, y, fg);

        bFill(x+1, y, bg, fg);
        bFill(x-1, y, bg, fg);
        bFill(x, y+1, bg, fg);
        bFill(x, y-1, bg, fg);
    }
}

void main(){
    startGraphics();
    setcolor(GREEN); //boundary's color will be green
    rectangle(50, 50, 75, 75); //make sure area of rectangle is small; Otherwise stack overflow ho jaayega
    fFill(60, 60, 0, 4); //0=black, 4=red
    getch();
    bFill(60, 60, 2, 9); //2=green, 9=blue
    getch();
    closegraph();
}