getting NullPointerException error

Vote count:

-1

I am new to java and was writing a simple program, but inspite of writing everything right I am getting an error. Please tell what my mistake is.. I can't figure it out.. Thank you :)

import javax.swing.*;
public class CarTrip{
private double distance;
private double fuel;
public CarTrip(){
   this.distance=0;
   this.fuel=0;
}
public CarTrip(double d,double f){
   this.distance=d;
   this.fuel=f;
}
public double getDistance(){
  return this.distance;
}
public double getFuel(){
  return this.fuel;
}
public void setDistance(double d){
  this.distance=d;
}
public void setFuel(double f){
  this.fuel=f;
}
public void addToTrip(double d,double f){
  this.distance=this.distance+d;
  this.fuel=this.fuel+f;
}
public  double fuelEfficiency(){
    return (http://ift.tt/1yOVTWv)*100;
 }
public void main(String[] args){
  CarTrip ct=new CarTrip();
  double d1=Double.parseDouble(JOptionPane.showInputDialog("Enter distance travelled for 1st segment"));
double f1=Double.parseDouble(JOptionPane.showInputDialog("Enter fuel used for 1st segment"));
ct.addToTrip(d1,f1);
double d2=Double.parseDouble(JOptionPane.showInputDialog("Enter distance travelled for 2nd segment"));
double f2=Double.parseDouble(JOptionPane.showInputDialog("Enter fuel used for 2nd segment"));
ct.addToTrip(d2,f2);
System.out.println(ct.fuelEfficiency());
}
}

asked 1 min ago

user3142334

31

getting NullPointerException error