Creating a toString from an array

Question

I am trying to create a toString to print the detail of my array. I can have it print how I want it to look by doing a for loop and using print line with in the toString but obviously dosn't really work when I want to use it in the main part of my code.

For context this is what I have for Card:

/** 
 * Constructor for the card. If damageDone and mana are negative they are replaced by 1 
 * (not the best solution but the good enough until we cover exception handling later in the 
 * semester). <br>
 * My solution length: 8 lines
 * @param manaCost - The amount of mana this spell costs to cast
 * @param damageDone - The amount of damage done by this card
 * @param name  - the name of this card
 */

public Card(int manaCost, int damageDone, java.lang.String name) {
    if (damageDone < 0) {
        this.damageDone = 1;}
    else {this.damageDone = damageDone;}
    if (manaCost < 0) {
        this.manaCost = 1;}
    else {this.manaCost = manaCost;}
    this.name = name;}

This is my example this piece of code works as to what I want it to look like but actually brings back no result:

public java.lang.String toString(){
    int count = 0;
    for (int index = 0; index < card.length; index++) {
        count++; 
        System.out.println(count + ": " + card[index]); 
    }
    return "";}

So I tried to build a string method but it brings back no results, I am so confused. Has anyone got any idea where I am going wrong.

@Override
public java.lang.String toString(){
    String output = "";
    for (int index = 0; index < card.length; index++) {
        output = output + card[index];
    }
    return output;}

The full class I am working on is below I am still having issues on other areas that I am working through:

public class Deck {

    private Card[] card = new Card[100];

private int cardsRunning = 100;
static int DECKSIZE = 100;
static java.lang.String emailID = "MITNY013";
private boolean random = true;



/**
 * Constructor for the Deck. Adds the following cards to the deck in the following order
 * 4x Super Lucky Strike, Damage 100, Mana 2 
 * 6x Mega Santa Hit, Damage 80, Mana 2
 * 10x Critical Hit, Damage 50, Mana 5
 * 10x Massive Strike, Damage 40, Mana 7
 * 15x Wrong Way Down A One Way Street, Damage 30, Mana 10
 * 15x Bender Rules Here, Damage 15, Mana 10
 * 40x Trade, Damage 5, Mana 5 <br>
 * My solution length: 16 lines (space lines not included)
 * @param random - Whether to turn on random features
 */

public Deck(boolean random) {
    for (int index = 0; index <= 3; index++) {
        card[index] = new Card( 2, 100, "Lucky Strike");
    }
    for (int index = 4; index <= 10; index++) {
        card[index] = new Card( 2, 80, "Santa Hit");
    }
    for (int index = 11; index <= 20; index++) {
        card[index] = new Card( 5, 50, "Critical Hit");
    }
    for (int index = 21; index <= 30; index++) {
        card[index] = new Card ( 7, 40, "Massive Strike");
    }
    for (int index = 31; index <= 45; index++) {
        card[index] = new Card( 10, 30, "Wrong Way Down A One Way Street");
    }
    for (int index = 46; index <= 60; index++) {
        card[index] = new Card( 10, 15, "Bender Rules Here");
    } 
    for (int index = 61; index <= 99; index++) {
        card[index] = new Card( 5, 5, "Trade");
    } 
}

/**
 * Returns a string representation of the entire deck in the format
 * Deck [ 1:Card [name=Super Lucky Strike, manaCost=2, damageDone=100]
 *        2:Card [name=Super Lucky Strike, manaCost=2, damageDone=100]
 *        3:Card [name=Super Lucky Strike, manaCost=2, damageDone=100]
 *        4:Card [name=Super Lucky Strike, manaCost=2, damageDone=100]] <br>
 * My solution length: 7 lines
 * @overrides - toString in class java.lang.Object
 */

@Override
public java.lang.String toString(){
    String output = "";
    for (int index = 0; index < card.length; index++) {
        output = output + card[index];
    }
    return output;}



/**
 * Uses a random number generator to get a card from the deck somewhere then swaps the 
 * last card in the deck to that position and reduces the cardsRemaining by one. 
 * This is important. if the random flag is false you should always get the card at 
 * position 0. When you swap the card out you should also set the old position to null 
 * for safety. <br>
 * My solution length: 10 lines
 * @return - the card drawn or null if no cards left in deck
 */

public Card getRandomCard() {
    // use random number generator
    Random rand = new Random();
    int randomCardNo = rand.nextInt(getCardsRemaining());
    removeCard(randomCardNo);
    return card[randomCardNo];
}

/**
 * Return the number of cards remaining in the deck.
 * My solution length: 6 lines
 * @return - the total cards remaining
 */

public int getCardsRemaining() {
    int temp = 100;
    for (int index = 0; index < card.length; index++) {
        if ((card[index] == null) ) {
            temp = temp -1;
        }}
    cardsRunning = temp;
    return cardsRunning;}

/**
 * BONUS Method
 * My solution length: XXX
 * @return - shuffle cards in deck 
 */

public void shuffle(Card[] card) {
    int index; 
    Card temp;
    Random random = new Random();
    for (int i = card.length - 1; i > 0; i--){ 
        index = random.nextInt(i + 1);
        temp = card[index];
        card[index] = card[i];
        card[i] = temp;}}

private void removeCard(int no) {
    int size = card.length;
    Card[] newCard = new Card[size];
    int index = 0;
    for (int i = 0; i < size; i++) {
        if (card[i] != null) {
            newCard[index++] = card[i];
        }
    }
    }
}

If `card.lenght > 0`, then something should be returned. Please post a [MRE]. --- A remark on your code: `java.lang.String` can be simplified to just `String`. The `java.lang` package is always implicitly imported. — Turing85, Feb 08 '20 at 21:45

Arvind Kumar Avinash · Answer 1 · 2020-02-08T23:55:51.177

You need to override the toString method in both, Card and Deck classes as given below:

public class Card {
    int manaCost;
    int damageDone;
    String name;

    public Card(int manaCost, int damageDone, String name) {
        if (damageDone < 0) {
            this.damageDone = 1;
        } else {
            this.damageDone = damageDone;
        }
        if (manaCost < 0) {
            this.manaCost = 1;
        } else {
            this.manaCost = manaCost;
        }
        this.name = name;
    }

    // ...

    @Override
    public String toString() {
        return "Card [manaCost=" + manaCost + ", damageDone=" + damageDone + ", name=" + name + "]";
    }
}

public class Deck {
    private Card[] cards;

    public void setCards(Card[] cards) {
        this.cards = cards;
    }

    // ...

    @Override
    public String toString() {
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < cards.length; i++) {
            sb.append(cards[i].toString() + "\n");
        }
        return sb.toString();
    }
}

Test:

public class Main {
    public static void main(String[] args) {
        Card[] cards= {
                new Card( 2, 100, "Lucky Strike"),
                new Card( 2, 80, "Santa Hit"),
                new Card( 5, 50, "Critical Hit")
        };
        Deck deck1 = new Deck();
        deck1.setCards(cards);
        System.out.println(deck1);
    }
}

Output:

Card [manaCost=2, damageDone=100, name=Lucky Strike]
Card [manaCost=2, damageDone=80, name=Santa Hit]
Card [manaCost=5, damageDone=50, name=Critical Hit]

Thanks Arvind, this has helped thank you. now I can move onto what is going wrong with my get random and get cards remaining — Nico, Feb 09 '20 at 01:00
@Nico - Do not forget to accept the answer so that future visitors can also use the solution confidently. Check https://meta.stackexchange.com/questions/5234/how-does-accepting-an-answer-work to learn how to do it. Feel free to comment in case of any doubt/issue. — Arvind Kumar Avinash, May 25 '20 at 19:22

score 0 · Answer 2 · answered Feb 08 '20 at 22:17

0

It would be nice to know what a card is. That being said, a really easy way to do this is using Arrays#toString.

public java.lang.String toString(){
    return Arrays.toString(card);
}

answered Feb 08 '20 at 22:17

Jason

5,154
2
12
22

Hi Jason, I have added what a Card is to my original message – Nico Feb 08 '20 at 23:33

Creating a toString from an array

2 Answers2