public class Reptile extends Animal{
  private static int number_of_legs;
  public Reptile(String name, int age, int weight, 
                 boolean poisonous, int number_of_legs){
    
    super(name, age, weight, poisonous);
    this.number_of_legs = number_of_legs;
  
  }
  
  public int compareTo(Object o){
    try{
      if(this.number_of_legs == ((Reptile)o).number_of_legs)
        return 0;
      else if(this.number_of_legs > ((Reptile)o).number_of_legs)
        return 1;
      else
        return -1;
    }catch(Exception e){
      //if the comparison fails, then we 
      //assume both are not Reptiles and 
      //must be compared in the superclass Animal
      return super.compareTo(o);
    }
  }
  
  public String toString(){
    return super.toString() + "\nnum_legs: " + number_of_legs;
  }
}