Question

Can you explain if my answer is correct and why the others are not?

Which line should be added into the removeCard method of class GroupOfCards? public class GroupOfCards { private ArrayList<Card> cards; // list of cards // Remove and return a card object at a specified location public Card removeCard(int index) { ________________ } // end removeCard } // end class GroupOfCards

A. cards[index] = null;

B. Card = cards.get(index); return card;

C. cards.remove(index); (correct answer)

D. return cards.remove(index);

E. Can’t decide as we don’t know the detail of class Card

My Response:The ArrayList collection class contains the object cards and it provides the remove() method. Method remove(int index) is used for removing an element of the specified index from a list.

Answer 1

option a:

it places null value in the place of object, it does not remove the object from the list.

option b:

Card = cards.get(index); return card;

is used to read the value from the specified index and return the card object as specified in the function prototype..

option c:

cards.remove(index);

it is used to remove the value or object from the specified lndex.

but does not return any card Object. function need to return card object

option D: [correct answer]

return cards.remove(index);  

we need to remove object or value from the specified location and need to return the object.

the above statement remove the object from index and return the card object.