my code is as follows:
class pottertr_Point{
private String name;
private double x;
private double y;
public pottertr_Point(){
name="Org";
x=(0);
y=(0);
}
public pottertr_Point getPoint(){
pottertr_Point p= new pottertr_Point();
p.name=this.name;
p.x=this.x;
p.y=this.y;
return p ;
}
public void setPoint(pottertr_Point p){
this.name=p.name;
this.x=p.x;
this.y=p.y;
}
public void setName(String name){
this.name=name;
}
public void setX(double x){
this.x=x;
}
public void setY(double y){
this.y=y;
}
public String getName(){
return name;
}
public double getX(){
return x;
}
public double getY(){
return y;
}
public double distance(pottertr_Point p){
double distance;
distance= Math.sqrt((this.x-p.x)*(this.x-p.x)+(this.y-p.y)*(this.y-p.y));
return distance;
}
}
public class Program5{
public static void main(String[] args){
pottertr_Point [] p =new pottertr_Point[3];
//pottertr_Point pp=new pottertr_Point();
String s=new String ("");
//p[0].setName(pp);
for (int i=0; i<3;i++){
s="p"+i;
p[i].setName(s);
p[i].setX(getCoordinate());
p[i].setY(getCoordinate());
System.out.println(p[i].getName()+", coordinate: (" + p[i].getX() + "," + p[i].getY());
}
for (int i=0;i<3;i++){
for (int j=i+1;j<3;j++){
System.out.println(p[i].getName()+ p[j].getName()+"distance"+p[i].distance(p[j]));
}
}
}
public static double getCoordinate(){
double r;
r=((int)(Math.random()*1.1))*10;
return r;
}
}
the error is at line 66 which is p[i].setName(s);
the error is java.lang.NullPointerException
any help will be useful. thank you.