import java.awt.*;
import java.applet.*;
public class Exm3 extends Applet
{
int vxmin,vymin,vxmax,vymax; //screen coordinates
double xmin,ymin,xmax,ymax; //imaginary coordinates
double dx; //interval of x
/* initializing */
public void init(){
xmin=-5;xmax=5;ymin=-3;ymax=7;
vxmin=0;vxmax=300;vymin=0;vymax=300;
dx=0.1;
}
public void paint(Graphics g){
double x1,y1,x2,y2;
//back color
g.setColor(new Color(255, 255, 192));
g.fillRect(vxmin,vymin,vxmax-vxmin,vymax-vymin);
// xy-coordinates
g.setColor(Color.black);
Line(g,0,ymin,0,ymax);
Line(g,xmin,0,xmax,0);
//graph
g.setColor(Color.blue);
x2=xmin;y2=func(x2);
for(x1=xmin;x1<=xmax;x1=x1+dx){
y1=func(x1);
Line(g,x1,y1,x2,y2);
x2=x1;y2=y1;
}
}
/* Convert imaginary coordinates to screen cordinates. */
public int mapX(double x){
int sx;
sx= vxmin+(int)((x-xmin)/(xmax-xmin)*(double)(vxmax-vxmin)) ;
return sx;
}
public int mapY(double y){
int sy;
sy=vymin+(int)((ymax-y)/(ymax-ymin)*(double)(vymax-vymin));
return sy;
}
/* Drawing Line */
public void Line(Graphics g,double x1,double y1,double x2,double y2){
g.drawLine(mapX(x1),mapY(y1),mapX(x2),mapY(y2));
}
/* Defining function */
public double func(double x){
double y;
y=x*x;
return y;
}
}
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