import greenfoot.*;  // (World, Actor, GreenfootImage, Greenfoot and MouseInfo)

/**
 * Write a description of class SnakeHead here.
 * 
 * @author (your name) 
 * @version (a version number or a date)
 */
public class SnakeHead extends Actor
{

private final int EAST = 0;
private final int SOUTH = 90;
private final int WEST = 180;
private final int NORTH = 270;

private final int SPEED = 10;
private int counter = 0;

public SnakeHead()
{
    GreenfootImage img = new GreenfootImage (20,20);
    img.fill();
    setImage(img);
    
    setRotation (Greenfoot.getRandomNumber(4)*90);
}
public void act()
{
moveAround();
    if(isTouching(Food.class)) {    
        removeTouching(Food.class);
         
        SnakeWorld world = (SnakeWorld)getWorld();
        world.addFood();
    }
}

private void moveAround()
{
counter ++;
if(counter==SPEED) {
move(1);
counter = 0;
}
if (Greenfoot.isKeyDown("right")) {
    setRotation(EAST);
}
if (Greenfoot.isKeyDown("down")) {
    setRotation(SOUTH);
}
if (Greenfoot.isKeyDown("left")) {
    setRotation(WAST);
}
if (Greenfoot.isKeyDown("up")) {
    setRotation(NORTH);
}
}
}

import greenfoot.*;  // (World, Actor, GreenfootImage, Greenfoot and MouseInfo)

/**
 * Write a description of class SnakeWorld here.
 * 
 * @author (your name) 
 * @version (a version number or a date)
 */
public class SnakeWorld extends World
{

    /**
     * Constructor for objects of class SnakeWorld.
     * 
     */
    public SnakeWorld()
    {    
        // Create a new world with 600x400 cells with a cell size of 1x1 pixels.
        super(30, 20, 20); 
        
        GreenfootImage img = new GreenfootImage(20,20);
        img.drawRect(0,0,19,19);
        setBackground(img);
        int x = Greenfoot.getRandomNumber(getWidth());
        int y = Greenfoot.getRandomNumber(getHeight());
        addObject (new SnakeHead(), x, y);
        
        addFood();
    }
    
    public void addFood()
    
   {
      int x = Greenfoot.getRandomNumber(getWidth());
      int y = Greenfoot.getRandomNumber(getHeight());
      addObject (new Food(), x, y); 
}
}

import greenfoot.*;  // (World, Actor, GreenfootImage, Greenfoot and MouseInfo)
import java.awt.Color;
/**
 * Write a description of class Food here.
 * 
 * @author (your name) 
 * @version (a version number or a date)
 */
public class Food extends Actor
{
    /**
     * Act - do whatever the Food wants to do. This method is called whenever
     * the 'Act' or 'Run' button gets pressed in the environment.
     */
    public Food () 
    {
       GreenfootImage img = new GreenfootImage(20,20);
       img.setColor(Color.GREEN);
       img.fill();
       setImage(img);
    }  
    public void act()
    {
        
        
    }
}