Bouncing Ball program in C language

#include<stdio.h>

#include<conio.h>

#include<graphics.h>

#include<dos.h>

void main() {

int gd = DETECT, gm = DETECT;

int x, y = 0, j, t = 400, c = 1;

initgraph(&gd, &gm, "");

setcolor(RED);

setfillstyle(SOLID_FILL, RED);

for (x = 40; x < 602; x++) {

cleardevice();

circle(x, y, 30);

floodfill(x, y, RED);

delay(40);

if (y >= 400) {

c = 0;

t -= 20;

}

if (y <= (400 - t))

    c = 1;

y = y + (c ? 15 : -15);

}

getch();

}