#include <graphics.h>

#include <stdlib.h>

#include <stdio.h>

#include <conio.h>

#include <math.h>

float f(int x);

void main()

{

int x,y;

int a=4;

int gdriver = DETECT, gmode, errorcode;

initgraph(&gdriver, &gmode, “”);

line(300,300,300,50);

line(300+200,175,100,175);

putpixel(300,175,GREEN);

for(x=0;x<1000;x++)

{

y=f(x);

putpixel(x+300, 175-y,GREEN);

putpixel(x+300, 175+y,GREEN);

}

getch();

closegraph();

}

float f(int x)

{

return 2*sqrt(4*x);

}

**initgraph ** is used for initialization of graph.

**line ** function is used to draw lines on screen.

**putpixel(300,175,GREEN); **is used to define an origin.

in for loop we use **f(x)** which return the value of **2*sqrt(4*x)**. The graph of this equation is always a parabola.

**putpixel(x+300, 175-y,GREEN); ** is used to draw a point to upper level of the origin.

**putpixel(x+300, 175+y,GREEN); ** is used to draw a point below the line or origin.