/* 
   +------------------+ 
   | Rat              | 
   +------------------+
   | int lifespan     |
   | Posn loc         |
   +------------------+
   | Rat starve()     |
   | Rat eat()        |
   | bool isDead()    |
   +------------------+
*/

// to represent a Rat
public class Rat{ 
  private int lifespan; 
  private Posn loc; 

  public Rat(Posn loc){ 
    this(loc,10); 
  }
  private Rat(Posn loc, int lifespan){ 
    this.loc = loc; 
    this.lifespan = lifespan; 
  }

  // produce a hungrier rat. 
  public Rat starve(){ 
    return new Rat(this.loc,this.lifespan-1); 
  }

  // produce a less hungrier rat. 
  public Rat eat(int foodsize){
    return new Rat(this.loc, this.lifespan + foodsize); 
  }

  // the rat is dead when lifespan is 0 
  public boolean isDead(){ 
    return lifespan == 0; 
  } 

  public String toString(){ 
    return 
      new String( "Rat: " + "\n" + 
                  "\t" + " loc: " + this.loc.toString() + "\n" +
                  "\t" + " lifespan: " + this.lifespan + "\n" ); 
  }
}