Java Program The lab this lesson introduces students to writing programs that co

Question

Java Program

The lab this lesson introduces students to writing programs that consist of multiple classes. By the end of this lab, students should be able to

write a class to define a type that contains instance data and methods

create multiple objects of that type

use objects of the same type independently

LinearPerson

A LinearPerson lives on a number line. At any time, he or she has a position, such as 0 or 3 or -5. He or she can move one position at a time. He or she has a direction of movement. So if a LinearPerson is moving right and is at position -3, the new position will be -2. If a LinearPerson is moving left and is at position -3, the new position will be -4.

The following describes the LinearPerson class:

You should decide the instance variables needed for LinearPerson.

As an example

Create a class LinearPersonPair that creates two LinearPerson objects, one using the no-argument constructor, the other object should be created at a given location. The program moves the objects in various directions and prints their final locations.

Explanation / Answer

class LinearPerson{

   int direction;
   int position;

   LinearPerson(){
       direction = 1;
       position = 0;
   }

   LinearPerson(int _position){
       position = _position;
       direction = 1;
   }

   public void turn() {
   // changes the direction of the LinearPerson (right to left, or left to right)
       direction *= -1;
   }
   public void move(){
       // moves the LinearPerson one position in his or her current direction
       position += direction;
   }
   public int getPosition() {
       // returns the current position of the LinearPerson
       return position;
   }

}

public class LinearPersonPair{

   public static void main(String[] argv) {

      LinearPerson sophie = new LinearPerson();
      // sophie is at position 0, moving right
      System.out.println("soohie's current position is " + sophie.getPosition());
       sophie.turn();
       // sophie is at position 0, moving left
       sophie.move();
       // sophie is at position -1, moving left
       System.out.println("soohie's current position is " + sophie.getPosition());
       sophie.move();
       // sophie is at position -2, moving left
       System.out.println("soohie's current position is " + sophie.getPosition());
       sophie.turn();
       // sophie is at position -2, moving right
       System.out.println("soohie's current position is " + sophie.getPosition());
       sophie.move();
       // sophie is at position -1, moving right
       System.out.println("soohie's current position is " + sophie.getPosition());

       LinearPerson mandy = new LinearPerson(5);
     
      System.out.println("mandy's current position is " + mandy.getPosition());
       mandy.turn();
      
       mandy.move();
      
       System.out.println("mandy's current position is " + mandy.getPosition());
       mandy.move();
      
       System.out.println("mandy's current position is " + mandy.getPosition());
       mandy.turn();
         
       mandy.move();
      
       System.out.println("mandy's current position is " + mandy.getPosition());
   }

}

Output :-

soohie's current position is 0
soohie's current position is -1
soohie's current position is -2
soohie's current position is -2
soohie's current position is -1
mandy's current position is 5
mandy's current position is 4
mandy's current position is 3
mandy's current position is 4

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