Develop a toString method for the Deck class. It should return a single string that represents the cards in the deck. When it's printed, this string should display the same results as the print method in Section 13.1.

Hint: You can use the + operator to concatenate strings, but it is not very efcient. Consider using java.lang.StringBuilder instead; see Section 10.11.

Code:

import java.util.Arrays;

import java.util.Random;

/**

* A deck of playing cards (of fixed length).

*/

public class Deck {

private Card[] cards;

/**

* Constructs a standard deck of 52 cards.

*/

public Deck() {

this.cards = new Card[52];

int index = 0;

for (int suit = 0; suit <= 3; suit++) {

for (int rank = 1; rank <= 13; rank++) {

this.cards[index] = new Card(rank, suit);

index++;

}

}

}

/**

* Constructs a deck of n cards (all null).

*/

public Deck(int n) {

this.cards = new Card[n];

}

/**

* Gets the internal cards array.

*/

public Card[] getCards() {

return this.cards;

}

/**

* Displays each of the cards in the deck.

*/

public void print() {

for (Card card : this.cards) {

System.out.println(card);

}

}

/**

* Returns a string representation of the deck.

*/

public String toString() {

return Arrays.toString(this.cards);

}

/**

* Randomly permutes the array of cards.

*/

public void shuffle() {

}

/**

* Chooses a random number between low and high, including both.

*/

private static int randomInt(int low, int high) {

return 0;

}

/**

* Swaps the cards at indexes i and j.

*/

private void swapCards(int i, int j) {

}

/**

* Sorts the cards (in place) using selection sort.

*/

public void selectionSort() {

}

/**

* Finds the index of the lowest card

* between low and high inclusive.

*/

private int indexLowest(int low, int high) {

return 0;

}

/**

* Returns a subset of the cards in the deck.

*/

public Deck subdeck(int low, int high) {

Deck sub = new Deck(high - low + 1);

for (int i = 0; i < sub.cards.length; i++) {

sub.cards[i] = this.cards[low + i];

}

return sub;

}

/**

* Combines two previously sorted subdecks.

*/

private static Deck merge(Deck d1, Deck d2) {

return null;

}

/**

* Returns a sorted copy of the deck using selection sort.

*/

public Deck almostMergeSort() {

return this;

}

/**

* Returns a sorted copy of the deck using merge sort.

*/

public Deck mergeSort() {

return this;

}

/**

* Reorders the cards (in place) using insertion sort.

*/

public void insertionSort() {

}

}