Total newbie and I am lost so far.

[Marc Guilbault]

I have two programs and I am trying to get them both to compile, one does, the other gives me errors and I not sure why.

Program 1

import edu.fcps.karel2.Robot;
import edu.fcps.karel2.Display;
public class Racer extends Athlete
{
   public Racer()
   {
   
      super();
   }
   public Racer(int y)
   {
      super(1, y, Display.EAST, Display.INFINITY);
   }
   public void jumpRight()
   {
      turnLeft();
      move();
      turnRight();
      move();
      move();
      turnRight();
      move();
      turnLeft();
   }   
   public void jumpLeft()
   {
      turnRight();
      move();
      turnLeft();
      move();
      move();
      turnLeft();
      move();
      turnRight();
   }
   public void pick(int n)
   {
      for(int i = 1; i<=n; i++)
      {
         pickBeeper();

      }      
   }
   public void put(int n)
   {
      for (int i = 1; i<=n; i++)
      {
         putBeeper();
      }
   }
   public void sprint (int n)
   {
      for(int i = 1; i<=n; i++)
      {
         move();
      } 
   }
}

Program 2

import edu.fcps.karel2.Robot;
   import edu.fcps.karel2.Display;
   import javax.swing.JOptionPane;
    public class Lab08
   {
       public static void Racer(int arg)
      {
         while(!arg.nextToABeeper())
         {
            if(arg.frontIsClear())
            {
               arg.move();
            }
            else
            {
               arg.jumpRight();
            }
         }
      }
       public static void main(String[] args) 
      {
         String filename = JOptionPane.showInputDialog("What robot world?");
         String type = JOptionPane.showInputDialog("What type of racer?");
      
       Display.openWorld("maps/"+filename+".map");
         Display.setSize(18, 16);
         Display.setSpeed(10);
      
         if(type.equals("Racer"))
         {
            race( new Racer(1) );
         }
         else if(type.equals("SteepleChaseRacer"))
         {
            race( new SteepleChaseRacer(1) );
         }
         else if(type.equals("BoxTopRacer"))
         {
            race( new BoxTopRacer(1) );
         }
         else
         {
            System.out.println("Invalid robot type.");
         }
      }
   }

I am getting this error message for lab 8

----jGRASP exec: javac -g Lab08.java
Lab08.java:11: int cannot be dereferenced
while(!arg.nextToABeeper())
^
Lab08.java:13: int cannot be dereferenced
if(arg.frontIsClear())
^
Lab08.java:15: int cannot be dereferenced
arg.move();
^
Lab08.java:19: int cannot be dereferenced
arg.jumpRight();
^
Lab08.java:34: cannot find symbol
symbol : class Racer
location: class Lab08
race( new Racer(1) );
^
Lab08.java:38: cannot find symbol
symbol : class SteepleChaseRacer
location: class Lab08


As I said I am a total newbie and I would really appreciate some help here.

Marc

[Henry Wong]

Marc Guilbault wrote:
Lab08.java:11: int cannot be dereferenced
while(!arg.nextToABeeper())
^

The arg variable is of a primative int variable type. It doesn't have a nextToABeeper() method.

Henry

[Campbell Ritchie]

Welcome to the Ranch

You should always use code tags; so you can see how they work and how much of an improvement they make, I have added them to your post.
There is something I don't like about those if-elses in the main method. I am not quite sure how to sort it out.
There is also something wrong with the race() method. Shouldn't that be an instance method of the Racer class. And you have got confusion; you are writing race() in one place and Racer() elsewhere. The compiler will surely complain about that.

[Marc Guilbault]

Thank you all for the code tag information. I will do my best to ensure I do this properly. So we have 4 small pieces of code and I am stumped.

Here they are:

BoxTop Racer

import edu.fcps.karel2.Robot;
import edu.fcps.karel2.Display;
public class BoxTopRacer extends Athlete
{
   public BoxTopRacer()
   {
   
      super();
   }
   public BoxTopRacer(int y)
   {
      super(1, y, Display.EAST, Display.INFINITY);
   }
   public void jumpRight()
   {
      turnLeft();
      move();
      turnRight();
      move();
      move();
      turnRight();
      move();
      turnLeft();
   }   
   public void jumpLeft()
   {
      turnRight();
      move();
      turnLeft();
      move();
      move();
      turnLeft();
      move();
      turnRight();
   }
   public void pick(int n)
   {
      for(int i = 1; i<=n; i++)
      {
         pickBeeper();

      }      
   }
   public void put(int n)
   {
      for (int i = 1; i<=n; i++)
      {
         putBeeper();
      }
   }
   public void sprint (int n)
   {
      for(int i = 1; i<=n; i++)
      {
         move();
      } 
   }
}

Racer

import edu.fcps.karel2.Robot;
import edu.fcps.karel2.Display;
public class Racer extends Athlete
{
   public Racer()
   {
   
      super();
   }
   public Racer(int y)
   {
      super(1, y, Display.EAST, Display.INFINITY);
   }
   public void jumpRight()
   {
      turnLeft();
      move();
      turnRight();
      move();
      move();
      turnRight();
      move();
      turnLeft();
   }   
   public void jumpLeft()
   {
      turnRight();
      move();
      turnLeft();
      move();
      move();
      turnLeft();
      move();
      turnRight();
   }
   public void pick(int n)
   {
      for(int i = 1; i<=n; i++)
      {
         pickBeeper();

      }      
   }
   public void put(int n)
   {
      for (int i = 1; i<=n; i++)
      {
         putBeeper();
      }
   }
   public void sprint (int n)
   {
      for(int i = 1; i<=n; i++)
      {
         move();
      } 
   }
}

Lab8

 import edu.fcps.karel2.Robot;
   import edu.fcps.karel2.Display;
   import javax.swing.JOptionPane;
    public class Lab08
   {
       public static void race(Racer arg)
      {
         while(!arg.nextToABeeper())
         {
            if(arg.frontIsClear())
            {
               arg.move();
            }
            else
            {
               arg.jumpRight();
            }
         }
      }
       public static void main(String[] args) 
      {
         String filename = JOptionPane.showInputDialog("What robot world?");
         String type = JOptionPane.showInputDialog("What type of racer?");
      
       Display.openWorld("maps/"+filename+".map");
         Display.setSize(18, 16);
         Display.setSpeed(10);
      
         if(type.equals("Racer"))
         {
            race( new Racer(1) );
         }
         else if(type.equals("SteepleChaseRacer"))
         {
            race( new SteepleChaseRacer(1) );
         }
         else if(type.equals("BoxTopRacer"))
         {
            race( new BoxTopRacer(1) );
         }
         else
         {
            System.out.println("Invalid robot type.");
         }
      }
   }

SteepleChase

import edu.fcps.karel2.Robot;
import edu.fcps.karel2.Display;
public class SteepleChaseRacer extends Athlete
{
   public SteepleChaseRacer()
   {
   
      super();
   }
   public SteepleChaseRacer(int y)
   {
      super(1, y, Display.EAST, Display.INFINITY);
   }
   public void jumpRight()
   {
      turnLeft();
      move();
      turnRight();
      move();
      move();
      turnRight();
      move();
      turnLeft();
   }   
   public void jumpLeft()
   {
      turnRight();
      move();
      turnLeft();
      move();
      move();
      turnLeft();
      move();
      turnRight();
   }
   public void pick(int n)
   {
      for(int i = 1; i<=n; i++)
      {
         pickBeeper();

      }      
   }
   public void put(int n)
   {
      for (int i = 1; i<=n; i++)
      {
         putBeeper();
      }
   }
   public void sprint (int n)
   {
      for(int i = 1; i<=n; i++)
      {
         move();
      } 
   }
}

The error I am getting is:

Lab08.java:38: race(Racer) in Lab08 cannot be applied to (SteepleChaseRacer)
race( new SteepleChaseRacer(1) );
^
Lab08.java:42: race(Racer) in Lab08 cannot be applied to (BoxTopRacer)
race( new BoxTopRacer(1) );
^
2 errors
1 warning

Any help would be most appreciated and my sincere thanks in advance. I am so new at this and I am struggling to understand what is wrong.

Marc

[Henry Wong]

Marc Guilbault wrote:
The error I am getting is:

Lab08.java:38: race(Racer) in Lab08 cannot be applied to (SteepleChaseRacer)
race( new SteepleChaseRacer(1) );
^

Any help would be most appreciated and my sincere thanks in advance. I am so new at this and I am struggling to understand what is wrong.

The error message is clear. The race() method takes a single Racer object as a parameter. You passed it a SteepleChaseRacer object, and SteepleChaseRacer is not a Racer. Perhaps you meant to have the SteepleChaseRace class subclass the Racer class?

Henry