Question

我的作业是coffeeTinGame程序。我写了但结果却达不到我的期望。我的程序返回：

之前的锡：[G，B，B，G，G]
  锡后：[G，B， - ，G，G]
  最后的豆子：   ģ

我希望结果如下：

之前的锡：[G，B，B，G，G] 锡后：[ - ， - ， - ， - ，G] 最后一个豆：G

它出了什么问题？有人可以帮帮我吗？

 public class CoffeeTinGame
    {
        // constant value for green bean
        private static final char GREEN = 'G';
        // constant value for blue bean
        private static final char  BLUE = 'B';
        // constant for removed beans 
        private static final char REMOVED = '-';

          /**
          * the main procedure
          */
         public static void main(String [] args){
            // initialise somme beans
            char[] beans = {GREEN, BLUE, BLUE, GREEN, GREEN};

            // count number of greens
            int greens = 0;
            for (char b : beans) {
                if (b == GREEN) {
                    greens++;
                }
            }
            // the expected last bean
            final char last = (greens % 2 == 1) ? GREEN : BLUE;
            // p0 = green parity /\ 
            // (p0=1 -> last=GREEN) /\ (p0=0 -> last=BLUE)

            // print the content of tin before the game
            putf("Tin before : %s %n", Arrays.toString(beans));

            // perform the game
            char lastBean = tinGame(beans);
            // lastBean = last \/ lastBean != last

            // print the content of tin and last bean
            putf("Tin after : %s %n", Arrays.toString(beans));

            // check if last bean as expected and print 
            if (lastBean == last) {
                putf("Last bean: %c", lastBean);
            } else {
                putf("Oops, wrong last bean: %c (expected: %c) %n", lastBean, last);
            }
         }

         /** 
          * Takes out any two beans randomly
          * @requirement: tin is not null /\ tin.length > 0
          * @modifies tin
          * @effects: repeatedly remove two beans from tin
          *     create an array to store two beans
          *     that are taken out from tin
          *     takes out two beans randomly
          */
         private static int[] takeTwo(char[] tin){
             int[] b = new int[2];
             int count = tin.length;
            // takes one bean randomly
            // until length of tin >= 2 and this bean is not remove

                 do {
                     b[0] = (int)(Math.random()*count);
                 } while (count >= 2 && tin[b[0]] == REMOVED);
                // takes the next bean randomly
                // until length of tin >= 2 and this bean is not remove
                // and this bean is different the first bean
                 do {
                     b[1] = (int)(Math.random()*count);
                 } while (count >= 2 && tin[b[1]] == REMOVED && b[0] == b[1]); 

             return b;
         }

         /**
          * determine the color of the last bean
          * @requirement: tin is not null /\ tin.length > 0
          * @effects: 
          *     {@link #takeTwo()}after taking out two beans
          *     if they are the same color 
          *         throw them both away
          *         put a Blue Mountain bean back in
          *     else 
          *         throw away the blue one
          *         put the green one back
          *     until the bean in the tin = 1
          */
          private static char[] updateTin(char[] tin){
         int b1, b2;
         // count is assigned to the length of tin
         int count = tin.length;
         /**
          * check condition: if two beans are the same color
          *     throw both away
          *     put Blue bean back 
          *  otherwise 
          *     put Green bean back
          */
         while (count >= 2){
             int[] a = takeTwo(tin);
             // remove beans in tin
             b1 = tin[a[0]];
             tin[a[0]] = REMOVED;
             b2 = tin[a[1]];
             tin[a[1]] = REMOVED;
             if (b1 == BLUE && b2 == BLUE || b1 == GREEN && b2 == GREEN){
                 // put blue in tin
                 tin[a[0]] = BLUE;
             } else {
                 // put green in tin
                 tin[a[0]] = GREEN;
             }

             // reduce the lengrh of tin
             count = count-1;
        }
         // return the bean in the tin
         return tin;
     }

         /**
          * perform the coffee tin game
          * @requirement: tin is not null /\ tin.length > 0
          * @effects:
          *     return color of the lastBean
          */
         private static char tinGame(char[] tin) {
             // invoke updateTin()
             char[] a = updateTin(tin);
             // initialise the last bean is removed
             char lastBean = REMOVED;
             int l = tin.length;

             for (int i = 0; i < l; i++){
                 if (a[i] != REMOVED){
                     // a[i] is not remove
                     // lastBean is a[i]
                     lastBean = a[i];
                     break;
                 }
             }
             // return color of the lastBean
             return lastBean;
         }
    }

Answer 1

在方法updateTin中将“if（b1 == BLUE＆amp;＆amp; b2 == BLUE || b1 == GREEN＆amp;＆amp; b2 == GREEN）”更改为“if（b1 == b2）”

在Java中找到最后一个bean的颜色

1 个答案: