Input Length And Width - Calculate And Print Perimeter And Area Of A Rectangle

Create a program to input the length and width of a rectangle and calculate and print the perimeter and area of the rectangle. To do this you will need to write a Rectangle class and a separate runner class. Your program should include instance variables, constructors, an area method, a perimeter method, a toString method, accessor and mutator methods, and user input. Your runner class should include 3 Rectangle objects. One default rectangle, one coded rectangle, and one user input rectangle. All methods should be tested in the runner class.

This is my code:

import java.util.Scanner;
 public class Rectangle {
double length;
double width;
public Rectangle() {

[Code] ...

What have I done??? I have created this program using the few different resources with which I am supplied, but I don't understand the resources.