我已经学习 Java 1 个月了。 这一次，我想创建一个扑克游戏。 关于我的程序有两个问题。 我希望有人可以帮助我解决它。
每张卡片都有它的价值，A为1，king为10，但我发现这是一个String数组。如何将每个“String value”作为“int value”进行操作？
String[] suits = { "hearts", "spades", "diamonds", "clubs" };
String[] number = {"A","2","3"......};
我希望这个系统第一次可以使用随机数来选择卡片，第二次运行时可以取消之前的数字（有52张卡片）。有什么办法可以解决这个问题吗？
【问题讨论】：
对于这种分类，您应该考虑的是枚举：
public enum Suit {
Hearts, Spades, Diamonds, Clubs;
}
public enum Card {
A, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, J, Q, K;
}
这有利于您的情况，因为枚举可以轻松地赋值给您喜欢的任何值，然后可以根据该值对它们进行比较。 事实上，Java 文档为introduction to enums 提供了一个纸牌游戏。
【讨论】：
对于您的第一个问题，您可以将卡片名称映射到它的值：
Map<String, Integer> values = new HashMap<String, Integer>();
values.put("A", 11);
values.put("2", 2);
// ...
values.put("King", 10);
// lookup a value:
int kingValue = values.get("King");
对于第二个，我会依赖 java shuffle 函数。创建所有卡片的列表
ArrayList<Card> deck = someMagicMethodToPopulateTheList();
然后简单地洗牌
Collections.shuffle(deck);
现在你可以遍历牌组，你会看到随机顺序的牌：
for (Card card:deck) {
System.out.println(card);
}
注意：Card 类不存在（目前）。我只是为了简单起见而发明了这个名字）
【讨论】：
我不认为你想要一个用于卡片的字符串数组，你真正需要的是一个enum。这是关于enum 类型的一个很好的教程：
http://docs.oracle.com/javase/tutorial/java/javaOO/enum.html
此外，以下是在 Java 中生成随机数的方法： http://javamex.com/tutorials/random_numbers/
【讨论】：
这可能超出了您的需要，但您可以使用枚举做很多事情：
package sample;
import java.util.*;
enum Rank {
joker(new Character('*'),"Joker"),aceLow(new Character('a'),"Ace(low)"),deuce(new Character('2'),"Deuce"),trey(new Character('3'),"Trey"),four(new Character('4'),"Four"),five(new Character('5'),"Five"),six(new Character('6'),"Six"),seven(new Character('7'),"Seven"),eight(new Character('8'),"Eight"),nine(new Character('9'),"Nine"),ten(new Character('T'),"Ten"),jack(new Character('J'),"Jack"),queen(new Character('Q'),"Queen"),king(new Character('K'),"King"),aceHigh(new Character('A'),"Ace");
Rank(final Character c,final String s) {
this.c=c;
this.s=s;
}
public static Rank fromInt(int n) {
for(Rank r:Rank.values())
if(r.ordinal()==n)
return r;
return null;
}
public static Rank fromCharacter(char c) {
for(Rank r:Rank.values())
if(r.c==c)
return r;
return null;
}
public static Rank[] fromCharacters(final String cards) {
final Rank[] rank=new Rank[5];
for(int i=0;i<5;i++)
rank[i]=Rank.fromCharacter(cards.charAt(i));
return rank;
}
public Character toCharacter() {
return c;
}
public String toString() {
return s;
}
public static String toString(final Rank[] rank) {
String s="";
for(Rank r:rank)
s+=r.toCharacter();
return s;
}
final Character c;
final String s;
}
enum Suit {
joker(new Character('*'),"Joker"),clubs(new Character('c'/* try character for a real dimond? */),"Club"),diamonds(new Character('d'),"Diamond"),hearts(new Character('h'),"Heart"),spades(new Character('s'),"Spade");
Suit(final Character c,final String s) {
this.c=c;
this.s=s;
}
public static Suit fromCharacter(char c) {
for(Suit s:Suit.values())
if(s.c==c)
return s;
return null;
}
public Character toCharacter() {
return c;
}
public String toString() {
return s;
}
public static String toString(final Suit[] suit) {
String s_="";
for(Suit s:suit)
s_+=s.toCharacter();
return s_;
}
public static boolean areSuited(final Suit[] suit) {
final int n=suit.length;
for(int i=0;i<n-1;i++)
if(suit[i]!=suit[i+1])
return false;
return true;
}
final Character c;
final String s;
}
enum Card {
joker(Rank.joker,Suit.joker),
aceLowOfClubs(Rank.aceLow,Suit.clubs),
aceLowOfDiamonds(Rank.aceLow,Suit.diamonds),
aceLowOfHearts(Rank.aceLow,Suit.hearts),
aceLowOfSpades(Rank.aceLow,Suit.spades),
dueceOfClubs(Rank.deuce,Suit.clubs),
dueceOfDiamonds(Rank.deuce,Suit.diamonds),
dueceOfHearts(Rank.deuce,Suit.hearts),
dueceOfSpades(Rank.deuce,Suit.spades),
treyOfClubs(Rank.trey,Suit.clubs),
treyOfDiamonds(Rank.trey,Suit.diamonds),
treyOfHearts(Rank.trey,Suit.hearts),
treyOfSpades(Rank.trey,Suit.spades),
fourOfClubs(Rank.four,Suit.clubs),
fourOfDiamonds(Rank.four,Suit.diamonds),
fourOfHearts(Rank.four,Suit.hearts),
fourOfSpades(Rank.four,Suit.spades),
fiveOfClubs(Rank.five,Suit.clubs),
fiveOfDiamonds(Rank.five,Suit.diamonds),
fiveOfHearts(Rank.five,Suit.hearts),
fiveOfSpades(Rank.five,Suit.spades),
sixOfClubs(Rank.six,Suit.clubs),
sixOfDiamonds(Rank.six,Suit.diamonds),
sixOfHearts(Rank.six,Suit.hearts),
sixOfSpades(Rank.six,Suit.spades),
sevenOfClubs(Rank.seven,Suit.clubs),
sevenOfDiamonds(Rank.seven,Suit.diamonds),
sevenOfHearts(Rank.seven,Suit.hearts),
sevenOfSpades(Rank.seven,Suit.spades),
eightOfClubs(Rank.eight,Suit.clubs),
eightOfDiamonds(Rank.eight,Suit.diamonds),
eightOfHearts(Rank.eight,Suit.hearts),
eightOfSpades(Rank.eight,Suit.spades),
nineOfClubs(Rank.nine,Suit.clubs),
nineOfDiamonds(Rank.nine,Suit.diamonds),
nineOfHearts(Rank.nine,Suit.hearts),
nineOfSpades(Rank.nine,Suit.spades),
tenOfClubs(Rank.ten,Suit.clubs),
tenOfDiamonds(Rank.ten,Suit.diamonds),
tenOfHearts(Rank.ten,Suit.hearts),
tenOfSpades(Rank.ten,Suit.spades),
jackOfClubs(Rank.jack,Suit.clubs),
jackOfDiamonds(Rank.jack,Suit.diamonds),
jackOfHearts(Rank.jack,Suit.hearts),
jackOfSpades(Rank.jack,Suit.spades),
queenOfClubs(Rank.queen,Suit.clubs),
queenOfDiamonds(Rank.queen,Suit.diamonds),
queenOfHearts(Rank.queen,Suit.hearts),
queenOfSpades(Rank.queen,Suit.spades),
kingOfClubs(Rank.king,Suit.clubs),
kingOfDiamonds(Rank.king,Suit.diamonds),
kingOfHearts(Rank.king,Suit.hearts),
kingOfSpades(Rank.king,Suit.spades),
aceOfClubs(Rank.aceHigh,Suit.clubs),
aceOfDiamonds(Rank.aceHigh,Suit.diamonds),
aceOfHearts(Rank.aceHigh,Suit.hearts),
aceOfSpades(Rank.aceHigh,Suit.spades);
private Card(Rank rank,Suit suit) {
this.rank=rank;
this.suit=suit;
}
public Rank rank() {
return rank;
}
public Suit suit() {
return suit;
}
public String toString() {
if(rank.equals(Rank.joker)||suit.equals(Suit.joker))
return "Joker";
else return rank+" of "+suit+'s';
}
public static String toString(final Card[] card) {
String s=new String();
for(int i=0;i<card.length;i++) {
if(i>0)
s+=", ";
s+=card[i].toCharacters();
}
return s;
}
public String toCharacters() {
return ""+rank().toCharacter()+suit().toCharacter();
}
public static Card instance(Rank rank,Suit suit) { // some hack for speed
final int n=4*rank.ordinal()+suit.ordinal();
//System.out.println(rank+" "+suit+" "+n);
return element[4*rank.ordinal()+suit.ordinal()];
}
static Card[] create(int standards,int jokers) {
int cards=0;
Card card[]=new Card[standards*52+jokers];
for(int i=0;i<standards;i++)
for(Suit suit:EnumSet.range(Suit.clubs,Suit.spades))
for(Rank rank:EnumSet.range(Rank.deuce,Rank.aceHigh))
card[cards++]=instance(rank,suit);
for(int i=0;i<jokers;i++)
card[cards++]=instance(Rank.joker,Suit.joker);
return card;
}
private final Rank rank;
private final Suit suit;
private static final Card element[]={joker,joker,joker,joker,joker,aceLowOfClubs,aceLowOfDiamonds,aceLowOfHearts,aceLowOfSpades,dueceOfClubs,dueceOfDiamonds,dueceOfHearts,dueceOfSpades,treyOfClubs,treyOfDiamonds,treyOfHearts,treyOfSpades,fourOfClubs,fourOfDiamonds,fourOfHearts,fourOfSpades,fiveOfClubs,fiveOfDiamonds,fiveOfHearts,fiveOfSpades,sixOfClubs,sixOfDiamonds,sixOfHearts,sixOfSpades,sevenOfClubs,sevenOfDiamonds,sevenOfHearts,sevenOfSpades,eightOfClubs,eightOfDiamonds,eightOfHearts,eightOfSpades,nineOfClubs,nineOfDiamonds,nineOfHearts,nineOfSpades,tenOfClubs,tenOfDiamonds,tenOfHearts,tenOfSpades,jackOfClubs,jackOfDiamonds,jackOfHearts,jackOfSpades,queenOfClubs,queenOfDiamonds,queenOfHearts,queenOfSpades,kingOfClubs,kingOfDiamonds,kingOfHearts,kingOfSpades,aceOfClubs,
aceOfDiamonds,aceOfHearts,aceOfSpades};
}
【讨论】：