java - 奶牛和公牛代码 - Java

Question

我是一名刚开始学习 CS 的学生，我一直在玩 Cows and Bulls 游戏。它编译并运行，但在某处存在某种我没有看到的错误，这会导致 Cows 和 Bulls 的数量不正确(预期输出与我的输出的样本)。

Cows和Bulls的解释:Bulls——正确数字的个数。奶牛 - 如果它们处于正确的位置，则正确的位数。

  public class CowsAndBulls{

  //Constants
  public final static int NUM_DIGITS = 4;
  public final static int MAX_VALUE = 9876;
  public final static int MIN_VALUE = 1234;
  public final static int MAX_GUESSES = 10;
  //


  // instances
  private NumberPicker randomNumber;
  private int answer;
  private int guessesCopy;
  private int bullStored;
  private int cowStored;
  //

  public CowsAndBulls(int seed){
        randomNumber = new NumberPicker(seed, MIN_VALUE, MAX_VALUE);
        answer = randomNumber.nextInt();
        guessesCopy = MAX_GUESSES;
        }

  ////////////////////////////////////////////////////////
  //Stuff between the comments is from a previous question that needs to be used in CowsAndBulls (not in a package) - I know it works as it's supposed to.
  public static int[] toArray(int number){

        String numString = Integer.toString(number);
        int[] someArray = new int[numString.length()];

        for (int i = 0; i < numString.length(); i++){
              char c = numString.charAt(i);

              int cVal = Character.getNumericValue(c);

              someArray[i] = cVal;
              }
        return someArray;
              }

  public static int countMatches(int a, int b){ //Bulls

        String stringA = Integer.toString(a);
        int lengthAB = stringA.length();
        int count = 0;

        int[] arrayOutA = toArray(a);
        int[] arrayOutB = toArray(b);

        for (int i = 0; i < lengthAB; i++){
              if (arrayOutA[i] == arrayOutB[i])
                    count += 1;     
                          }                   
        return count;
        } 


  public static int countIntersect(int numA, int numB){ //Cows
        String stringA = Integer.toString(numA);
        int lengthAB = stringA.length();
        int count = 0;

        int[] arrayOutA = toArray(numA);
        int[] arrayOutB = toArray(numB);

        for (int i = 0; i < lengthAB; i++){

              for (int j = 0; j < lengthAB; j++){

                    if ( arrayOutA[i] == arrayOutB[j]){
                             count += 1;
                             }
                          }

                    }
                    return count;
                    } 
  //////////////////////////////////////////////////////////////////                        






  public int guessesRemaining(){
        return guessesCopy;
        }



  public Result guess(int guessNumber){

        int bulls = countMatches(answer, guessNumber);
        bullStored = bulls;
        int cows = countIntersect(answer, guessNumber);
        cowStored = cows;

        guessesCopy--;
        return (new Result(cows, bulls));
        }

  public int giveUp(){
        return (answer);
        }

  public boolean gameOver(){
        if (guessesCopy == 0 || bullStored == 4)
              return true;
        else
              return false;                  
        }

下面是我们应该使用的提供的类，不能以任何方式编辑:NumberPicker、Game 和 Result。数字选择器:

    import java.util.ArrayList;
    import java.util.Collections;
    import java.util.List;
    import java.util.Random;
    /**
     * Given a number range, a NumberPicker returns the numbers in the range   in a random order
   */
    public class NumberPicker {

          private List<Integer> numbers;

    /**
      * Create a NumberPicker that uses the given seed value for  randomisation and that 
      * returns the numbers in the range min to max (inclusive) in a random order.
       * /
       public NumberPicker(final int seed, final int min, final int max) {
            numbers = new ArrayList<Integer>();
            final Random random = new Random(seed);
            for(int i = min; i<max+1; i++) {
            numbers.add(i);
                }
            Collections.shuffle(numbers, random);
            }

       /**
        * Determine whether the NumberPicker contains any more numbers..
        */
        public boolean hasNext() { return !numbers.isEmpty(); }

        /**
        * Return a randomly selected number from the range.
        */
      public int nextInt() { return numbers.remove(0); }

    }

游戏类:

             import java.util.Scanner;

             public class Game {

             private Game() {}

            public static void main(String[] inputs) {
         Scanner input = new Scanner(System.in);
         System.out.println("Your challenge is to guess a secret " +  CowsAndBulls.NUM_DIGITS + " digit number.");

         System.out.println("Enter randomisation seed value:");
         CowsAndBulls cowsAndBulls = new CowsAndBulls(input.nextInt());

         System.out.println("Make a guess:");
         Result answer = cowsAndBulls.guess(input.nextInt());

        while(!answer.isCorrect()&&cowsAndBulls.guessesRemaining()>0) {

            System.out.println("Sorry that's incorrect.");
            System.out.println("You have "+answer+".");

            System.out.printf("You have %d guesses remaining\n", cowsAndBulls.guessesRemaining());
            System.out.println("Make a guess:");
            answer = cowsAndBulls.guess(input.nextInt());
             }
         if (answer.isCorrect()) {
             System.out.println("Correct !");
             }
         else {
             System.out.println("Sorry, you lose.");
             }
           }
         }

最后，结果类:

            /**
            * A Result object records the outcome of a guess in the Cows and Bulls guessing game.
            * 
            * 
            */
        public class Result {

            private int cows;
            private int bulls;

      public Result(int cows, int bulls) {
           assert(cows+bulls<=4);
           this.cows=cows;
           this.bulls=bulls;
           }

        public int cows() { return cows; }
        public int bulls() { return bulls; }

        public boolean isCorrect() { return bulls==4; }

        public boolean equals(Object o) {
           if (!(o instanceof Result)) {
                 return false;
                 }
           else {
                Result other = (Result)o;
              return this.cows()==other.cows()&&this.bulls()==other.bulls();
             }
       }

      public String toString() {
          String result = this.cows()+(this.cows()!=1 ? " cows" : " cow");
          result = result+" and "+this.bulls()+(this.bulls()!=1 ? " bulls" : " bull");
          return result;
          }

    }

这就是全部代码。重申一下:我无法更改除 CowsAndBulls 之外的任何类，并且我必须使用 Game、Result 和 NumberPicker。以下是预期输出与我的程序产生的结果...

       Trial 1: Output not correct

       The expected output was:
       10
       false
       8913
       true

       Your program produced:
       10
       false
       7407
       false

       Input supplied to your program:
       construct 3
       guessesRemaining()
       gameOver()
       giveUp()
       gameOver()
       Q

       -------------------------------------
       Trial 2: Output not correct

       The expected output was:
       10
       0 cows and 0 bulls
       9
       1 cow and 0 bulls
       8
       2 cows and 0 bulls
       7
       3 cows and 0 bulls
       6
       4 cows and 0 bulls
       5

       Your program produced:
       10
       1 cow and 0 bulls
       9
       0 cows and 0 bulls
       8
       1 cow and 0 bulls
       7
       2 cows and 0 bulls
       6
       2 cows and 0 bulls
       5

       Input supplied to your program:
       construct 4
       guessesRemaining()
       guess() 2358
       guessesRemaining()
       guess() 1235
       guessesRemaining()
       guess() 1735
       guessesRemaining()
       guess() 1749
       guessesRemaining()
       guess() 1746
       guessesRemaining()
       Q
       ----------------------------------------------
       Trial 3: Output not correct

       The expected output was:
       10
       0 cows and 0 bulls
       9
       0 cows and 1 bull
       8
       0 cows and 2 bulls
       7
       0 cows and 3 bulls
       6
       0 cows and 4 bulls
       5
       true

       Your program produced:
       10
       1 cow and 0 bulls
       9
       1 cow and 0 bulls
       8
       1 cow and 0 bulls
       7
       1 cow and 0 bulls
       6
       1 cow and 0 bulls
       5
       false

       Input supplied to your program:
       construct 8
       guessesRemaining()
       guess() 2358
       guessesRemaining()
       guess() 2758
       guessesRemaining()
       guess() 2748
       guessesRemaining()
       guess() 6748
       guessesRemaining()
       guess() 6741
       guessesRemaining()
       gameOver()
       Q

这可能只是我没有看到的一些愚蠢的东西，但非常感谢任何帮助。我是 S.E(和 Java)的新手，所以我的代码格式可能很奇怪 - 如果是这样，我会编辑它。谢谢 :)。

Answer 1

   The expected output was:
   10
   false
   8913
   true

   Your program produced:
   10
   false
   7407
   false

   Input supplied to your program:
   construct 3
   guessesRemaining()
   gameOver()
   giveUp()
   gameOver()
   Q

据我所知，它告诉您它期望从 giveUp() 获得的数字不正确。这表明您的程序以某种方式生成不同的数字(7404 与 8913)。这可能是由于您的 MIN_VALUE 和/或 MAX_VALUE？

public static int countIntersect(int numA, int numB) { //Cows
    String stringA = Integer.toString(numA);
    int lengthAB = stringA.length();
    int count = 0;

    int[] arrayOutA = toArray(numA);
    int[] arrayOutB = toArray(numB);

    for (int i = 0; i < lengthAB; i++) {

        for (int j = 0; j < lengthAB; j++) {

            if (arrayOutA[i] == arrayOutB[j]) {
                count += 1;
            }
        }

    }
    return count;
}

我认为这不是您想要的。例如 countIntersect(1111,1111) 将返回 16，我希望这是 4 或 0？

关于您的编码，这里有一些小的反馈:

在函数 giveUp 中，您不需要在 return 语句中使用 ( 和 )。

// Original
public int giveUp() {
    return (answer);
}

// Suggested
public int giveUp() {
    return answer;
}

在您的 guess 函数中，您不需要先将其保存在本地 int 中。还有 ( 和 )。

// Original
public Result guess(int guessNumber) {

    int bulls = countMatches(answer, guessNumber);
    bullStored = bulls;
    int cows = countIntersect(answer, guessNumber);
    cowStored = cows;

    guessesCopy--;
    return (new Result(cows, bulls));
}

// Suggested
public Result guess(int guessNumber) {
    bullStored = countMatches(answer, guessNumber);
    cowStored = countIntersect(answer, guessNumber);
    guessesCopy--;
    return new Result(cowStored, bullStored);
}

在您的方法 countIntersect 中，没有理由使用特殊的 int[] 数组。字符数组也可以。此外，lengthAB 可以替换为 2 个数组之一的 .length 属性。

// Original
public static int countIntersect(int numA, int numB) { //Cows
    String stringA = Integer.toString(numA);
    int lengthAB = stringA.length();
    int count = 0;

    int[] arrayOutA = toArray(numA);
    int[] arrayOutB = toArray(numB);

    for (int i = 0; i < lengthAB; i++) {
        for (int j = 0; j < lengthAB; j++) {
            if (arrayOutA[i] == arrayOutB[j]) {
                count += 1;
            }
        }
    }
    return count;
}

// Suggested
public static int countIntersect(int numA, int numB) { //Cows
    int count = 0;

    char[] arrayA = Integer.toString(numA).toCharArray();
    char[] arrayB = Integer.toString(numB).toCharArray();

    for (int i = 0; i < arrayA.length; i++) {
        for (int j = i; j < arrayB.length; j++) {
            if (arrayA[i] == arrayB[j]) {
               if(i != j) {
                   count++;
               }
               break;
            }
        }
    }
    return count;
}

countMatches 也是如此。

// Original
public static int countMatches(int a, int b){ //Bulls

    String stringA = Integer.toString(a);
    int lengthAB = stringA.length();
    int count = 0;

    int[] arrayOutA = toArray(a);
    int[] arrayOutB = toArray(b);

    for (int i = 0; i < lengthAB; i++){
        if (arrayOutA[i] == arrayOutB[i])
            count += 1;
    }
    return count;
}

// Suggested
public static int countMatches(int a, int b) { //Bulls
    int count = 0;

    char[] arrayA = Integer.toString(a).toCharArray();
    char[] arrayB = Integer.toString(b).toCharArray();

    for (int i = 0; i < Math.min(arrayA.length,arrayB.length); i++) {
        if (arrayA[i] == arrayB[i])
            count += 1;
    }
    return count;
}

最后，您的 gameOver 可以写得更简单了。

//Original
public boolean gameOver() {
    if (guessesCopy == 0 || bullStored == 4)
        return true;
    else
        return false;
}

// Suggested
public boolean gameOver() {
    return guessesCopy == 0 || bullStored == 4;
}