使用构造函数创建对象

Question

I've a created a class called "Animal" as shown below:

class Animal{
int eyes,legs;
}

I've four more class which will inherit Animal class as shown below:

 class Monkey extends Animal
 {
 int hands;
 Monkey(){
 super.eyes=2;
 super.legs=2;
 hands=2;
 }
 }

  class squirell extends Animal{
 int hands;
 int hands;
 Squirrel(){
 super.eyes=2;
 super.legs=2;
 hands=2;
 }
 }


 class piegon extends Animal{

 int wings;
piegon(){
super.eyes=2;
super.legs=2;
wings=2;
}
}


class eagle extends Animal{

int wings;
eagle(){
super.eyes=2;
super.legs=2;
wings=2;
}
}   

And I've Ladder class which uses "contains" relationship.. Ladder "contains" Monkey,Eagle,Piegon etc..

Here I want to create ladder object and I want to "place" various animals on ladder.

I wanted to create various animal objects using constructor of Ladder class. How can I do that?? Can anyone help me.?

Answer 1

I'm not quite sure what your complete goal is, but in order to "Place" these objects onto your ladder, you might want something like:

class Ladder {
  private List<Animal> animalsOnLadder = new ArrayList<Animal>;

  public Ladder() {
    placeAnimalOnLadder(new eagle());
    placeAnimalOnLadder(new squirell());

  }

  public void placeAnimalOnLadder(Animal animal) {
    animalsOnLadder.add(animal);
  }

}

Answer 2

class Ladder {
    Squirrel s = new Squirrel();
    Pigeon p = new Pigeon();
}

etc...

You'll probably want to put the scope of the "animals" outside of the constructor though:

Squirrel s; Pigeon p;
class Ladder {
    s = new Squirrel();
    p = new Pigeon();
}