问题
In my game's code, I am trying to add a card to hand. As soon as I do, my array is out of bounds. Everything looks right, but maybe I'm missing something.
FYI, one and two are Player instances. Relevant code from Main class (sorry about the formatting. i suck at transferring it to Stack Overflow):
import java.util.*;
public class Program {
public static void main(String args[]) {
String[] rank = {"two", "three", "four", "five", "six", "seven", "eight",
"nine", "ten", "jack", "queen", "king", "ace"};
String[] suit = {"hearts", "diamonds", "spades", "clubs"};
Scanner scan = new Scanner(System.in);
String something = "yes", something2 = "yes"; //Use with while loop
String winner = "yes"; //Use for while loop
String temp; //Use with setting names
Card[] deck = new Card[52]; //Deck array
int playercount = 0;
Player one = new Player("temp");
Player two = new Player("temp");
Player three = new Player("temp");
Player four = new Player("temp");
while (something2.equals("yes") || playercount < 2) { //Add players to game
System.out.println("Would a(nother) player like to join?");
something2 = scan.nextLine();
System.out.println();
if (something2.equals("yes")) {
if (playercount <= 4) {
if (playercount == 0) {
System.out.println("What is your name: ");
Player one1 = new Player(scan.nextLine());
one = one1;
playercount++;
System.out.println();
}
else if (playercount == 1) {
System.out.println("What is your name: ");
Player two2 = new Player(scan.nextLine());
two = two2;
playercount++;
System.out.println();
}
else if (playercount == 2) {
System.out.println("What is your name: ");
Player three3 = new Player(scan.nextLine());
three = three3;
playercount++;
System.out.println();
}
else if (playercount == 3) {
System.out.println("What is your name: ");
Player four4 = new Player(scan.nextLine());
four = four4;
playercount++;
System.out.println();
}
else {System.out.println("Only four players are allowed.");
something2 = "no";}
}
}
else if (playercount < 2) {
System.out.println("You need at least two players...");
System.out.println();
}
else something2 = "no";
}
//Start game
while (something.equals("yes")) {
//Prepare game
Card.makeDeck(deck, rank, suit);
deck = Card.getDeck();
Card.shuffle(deck);
deck = Card.getDeck();
//Deal cards
if (playercount == 2) {
for (int i = 1; i < 8; i++) {
one.addCard(Card.draw(deck));
deck = Card.getDeck();
two.addCard(Card.draw(deck));
deck = Card.getDeck();
}
}
else if (playercount == 3) {
for (int i = 1; i < 8; i++) {
one.addCard(Card.draw(deck));
deck = Card.getDeck();
two.addCard(Card.draw(deck));
deck = Card.getDeck();
three.addCard(Card.draw(deck));
deck = Card.getDeck();
}
}
else {
for (int i = 1; i < 8; i++) {
one.addCard(Card.draw(deck));
deck = Card.getDeck();
two.addCard(Card.draw(deck));
deck = Card.getDeck();
three.addCard(Card.draw(deck));
deck = Card.getDeck();
four.addCard(Card.draw(deck));
deck = Card.getDeck();
}
}
}
}
}
Card class:
import java.util.*;
public class Card {
private String suit;
private String rank;
private static int temp = 0, temp2 = 0; //Use for reseting rank and suit
private static Card temp3; //Use for draw method
private static int temp4; //Use for shuffle method
private static Card[] deck = new Card[52];
//Constructors
public Card() {
this.rank = "two";
this.suit = "hearts";
}
public Card(String r, String s) {
this.rank = r;
this.suit = s;
}
//Mutators
//Make deck
public static void makeDeck(Card[] c, String[] r, String[] s) {
for (int i = 0; i < c.length; i++) {
c[i] = new Card(r[temp], s[temp2]);
temp++; temp2++;
//Reset rank and suit
if (temp > 12)
temp = 0;
if (temp2 > 3)
temp2 = 0;
}
deck = c;
}
//Accessors
//Return deck
public static Card[] getDeck() {
return deck;
}
//Shuffle
public static Card[] shuffle(Card[] c) {
for (int i = 0; i < c.length; i++) {
int rand = (int)(Math.random()*(i + 1));
//Don't let anything be in a slot that doesn't exist
while (rand > c.length) {
temp4 = (int)Math.random();
rand -= temp4;
}
if (rand < 0)
rand += temp4;
Card temp = c[i];
c[i] = c[rand];
c[rand] = temp;
}
deck = c;
return deck;
}
//Draw
public static Card draw(Card[] c) {
if (c != null) {
for (int i = 0; i < c.length; i++) {
if (c[i] != null) {
try {
return c[i];
} finally {
c[i] = null;} //Remove i from c
}
}
}
return null;
}
}
Player class:
import java.util.*;
public class Player {
private String name;
private Card[] hand = new Card[52];
private int handsize = 0;
//Constructor
public Player(String n) {
name = n;
}
//Mutators
public void addCard(Card c) {
hand[handsize] = c;
handsize++;
}
//Accessors
public String getName() {
return name;
}
public Card[] getHand() {
return hand;
}
}
回答1:
The problem is with your loop
while (something.equals("yes"))
There's nothing that sets something to any other value, so this loop just goes around endlessly, until all the players have more than 52 cards. Once someone has more than 52 cards, adding a new card causes the exception.
I think you need to remove this while. The code inside it should only be run once.
回答2:
Your draw method is broken.
// get the first non-null Card from the cards "c".
public static Card draw(Card[] c) {
if (c != null) {
for (int i = 0; i < c.length; i++) {
if (c[i] != null) {
try {
return c[i];
} finally {
// now remove element i from the `c` array.
c[i] = null;
}
}
}
}
return null;
}
回答3:
I think the order of your code is incorrect (hard to tell with this code)
for (int i = 1; i < 8; i++)
{
one.addCard(Card.draw(deck));
deck = Card.getDeck();
two.addCard(Card.draw(deck));
deck = Card.getDeck();
}
maybe should be
for (int i = 1; i < 8; i++)
{
deck = Card.getDeck();
one.addCard(Card.draw(deck));
deck = Card.getDeck();
two.addCard(Card.draw(deck));
}
Update
Also
public void addCard(Card c) {
hand[handsize] = c;
handsize++;
}
handsize is never incremented - it is always 0
来源：https://stackoverflow.com/questions/20648171/java-array-index-out-of-bounds-somehow