我正在编写一个掷骰子程序。在上课时，我还是Java的新手。我在该程序的不同程序包中使用多个类，我试图找出的是，在一个类中，对于我的程序包pairOfDice，我在pairOfDice，die1和die2类中创建了对象。现在，我还有另一个包rollDice，我的目标是使用pairOfDice类滚动两个骰子并显示滚动。我正在努力的是如何做到这一点。当我滚动骰子时，结果显示就好像我只是滚动一个骰子一样。我已经进行过调整，每卷显示两个骰子，尽管感觉好像我没有以一种更熟练的方式来做。
package die;
import java.util.Scanner;
/**
*
* @author <a href= "mailto:adavi125@my.chemeketa.edu" >Aaron Davis</a>
*/
public class RollDice
{
public static void main(String[] args)
{
Scanner scan = new Scanner(System.in);
PairOfDice dice = new PairOfDice();
// get amount of rolls from user
System.out.print("How many rolls do you want? ");
int numRolls = scan.nextInt();
int diceOne, diceTwo;
int boxCar, snakeEyes;
int j = 0, k = 0;
// rolls the dice the requested amount of times
for (int i = 0; i < numRolls; i++)
{
// first die to roll
diceOne = dice.roll();
// second die to roll
diceTwo = dice.roll();
// display rolled dice
System.out.println(diceOne + " " + diceTwo + "\n");
// store and display pairs of 1 rolls
if (diceOne == 1 && diceTwo == 1)
{
snakeEyes = ++j;
System.out.println("\nThe number of snake eyes you have is: "
+ snakeEyes + "\n");
}
// store and display pairs of 6 rolls
if (diceOne == 6 && diceTwo == 6)
{
boxCar = ++k;
System.out.println("\nThe number of box cars you have is: "
+ boxCar + "\n");
}
}
}
}
******************************************************************************
/*
the integers diceOne and diceTwo are my workarounds, my other package contains
public class PairOfDice extends Die
{
Die die1, die2;
public PairOfDice()
{
die1 = new Die();
die2 = new Die();
}
public PairOfDice(int face)
{
die1 = new Die(face);
die2 = new Die(face);
}
}
*/
******************************************************************************
// i am un-clear how to make "PairOfDice dice = new PairOfDice();" come out as two die
答案 0 :(得分：0)
PairOfDice类不代表您的模型，即“一对骰子”。
如果您有一对骰子，则在滚动它们时会得到两个不同的数字，即：
roll方法必须返回两个值。您可以使用包含两个值的RollResult bean roll方法只能返回2到12之间的整数，并且可以基于它们的总和推测骰子滚动：在您的情况下，总是有可能的，因为当且仅当得到2的总和如果您的骰子是1，1;同样，如果且仅当您的骰子为6、6时，您的总和为12。
例如，如果您要针对条件“骰子1 = 3，骰子2 = 4”进行测试，则将不起作用，因为滚动的许多组合返回3 + 4 = 7 希望这会有所帮助。
根据评论，我们必须继续第一个解决方案。
这里是一个示例，该示例实现了域不变对象和roll域函数，它们针对骰子返回roll操作的结果。
在此示例中，我展示了具有多种类型的骰子的可能性。
import java.util.*;
import java.util.stream.Collectors;
public class RollingDices {
private static final Random RND = new Random();
private static interface Dice {
public int roll();
}
private static class UniformDice implements Dice {
public int roll() {
return RND.nextInt(6) + 1;
}
}
private static class TrickyDice implements Dice {
private final int value;
public TrickyDice(int value) {
this.value = value;
}
public int roll() {
return value;
}
}
private static class ProbabilityTableDice implements Dice {
private final Double[] probabilities;
public ProbabilityTableDice(Double ... probabilities) {
if (Arrays.stream(probabilities).mapToDouble(Double::doubleValue).sum() != 1.0) {
throw new RuntimeException();
}
this.probabilities = probabilities;
}
public int roll() {
final double randomValue = RND.nextDouble();
double curValue = 0.0;
for (int i = 0; i < this.probabilities.length; i++) {
curValue += this.probabilities[i];
if (curValue >= randomValue) {
return i + 1;
}
}
throw new RuntimeException();
}
}
private static class CollectionOfDices {
private final Dice[] dices;
public CollectionOfDices(Dice ... dices) {
this.dices = dices;
}
public List<Integer> roll() {
return Arrays.stream(dices).map(Dice::roll).collect(Collectors.toList());
}
}
private static class DicesFactory {
private static final DicesFactory INSTANCE = new DicesFactory();
public static DicesFactory instance() {
return INSTANCE;
}
private DicesFactory() {}
private final Dice uniformDice = new UniformDice();
public Dice createUniformDice() {
return this.uniformDice;
}
public Dice createTrickyDice(int fixedValue) {
return new TrickyDice(fixedValue);
}
public Dice createProbabilityTableDice(Double ... probabilities) {
return new ProbabilityTableDice(probabilities);
}
}
public static void main(String ... args) {
final Scanner scan = new Scanner(System.in);
final CollectionOfDices dice = new CollectionOfDices(
DicesFactory.instance().createUniformDice(),
DicesFactory.instance().createProbabilityTableDice(
0.15, 0.2, 0.3, 0.1, 0.25
)
);
// get amount of rolls from user
System.out.print("How many rolls do you want? ");
int numRolls = scan.nextInt();
int diceOne, diceTwo;
int boxCar, snakeEyes;
int j = 0, k = 0;
// rolls the dice the requested amount of times
for (int i = 0; i < numRolls; i++)
{
final List<Integer> rolls = dice.roll();
// first die to roll
diceOne = rolls.get(0);
// second die to roll
diceTwo = rolls.get(1);
// display rolled dice
System.out.println(diceOne + " " + diceTwo + "\n");
// store and display pairs of 1 rolls
if (diceOne == 1 && diceTwo == 1)
{
snakeEyes = ++j;
System.out.println("\nThe number of snake eyes you have is: "
+ snakeEyes + "\n");
}
// store and display pairs of 6 rolls
if (diceOne == 6 && diceTwo == 6)
{
boxCar = ++k;
System.out.println("\nThe number of box cars you have is: "
+ boxCar + "\n");
}
}
}
}