平均模式方法的两个问题

Question

这是我完成的代码，用于计算均值、中值、众数、标准差、最小值、最大值、q1、q2 和 5 个数字摘要，这些摘要应该被 return 编辑为数组。据我所知，该数组的格式正确，但由于某些奇怪的原因，return 数组吐出了这个 5 number Summary:[D@689af4，我终其一生都不知道为什么或如何修复它。当我需要它输出 -1 时，模式也输出 22。有没有人可以看看这个并告诉我哪里出了问题以及我可以做些什么来解决这些问题？

import java.util.Arrays;

class Statistics {
  public static void main(String[] args)
  {
     int[] a = new int[]{22,44,66,55,33};

           bubbleSort(a);
           double mean; 
           double median; 
           int mode;
           int max;
           int min;
           double sd;
           int q1; 
           int q3; 
           double[] vals; 


           mode = calcMoe (a);
           median = calcMed (a);
           mean = calcMean (a);
           max =calcMax (a);
           min =calcMin (a);
           sd =calcSd (a);
           q1=calcQuart1 (a); 
           q3=calcQuart3 (a); 
           vals=calcNumsum (a);



           System.out.println("Median:"+median); 
           System.out.println("Mean:"+mean); 
           System.out.println("Mode:"+mode);
           System.out.println("max number is : " + max);
           System.out.println("min number is : " + min);
           System.out.println("Standard Deviation:"+sd);
           System.out.println("1st Quartile:"+q1); 
           System.out.println("3rd Quartile:"+q3);
           System.out.println("5 number Summary:"+vals);

  }



  public static double calcMean(int[] a)
  {

  // int[]array = {22,44,66,55,33}; 
    int i;//=0;
    int sum=0;
    double mean =0;
    for ( i=0;i<a.length;i++)
    { 
      //System.out.println(a[i]);
      sum=sum+a[i];
    }
    {  mean = ((double) sum/ ((double) a.length));
      //System.out.println(); } {

        return mean;}
      } 
   //Calulate median

   public static double calcMed(int[] a)
 {// Sort array 
  int[] sorta = bubbleSort(a);

  double median = 0;
  if (a.length % 2 == 0)

   {
    int indexA = (sorta.length - 1) / 2;
   int indexB = sorta.length / 2;

   median = ((double) (sorta[indexA] + sorta[indexB])) / 2;
  }
 // Else if our array's length is odd
  else  
  {
   int index = (sorta.length - 1) / 2;
   median = a[ index ];
  }

  // Print the values of the sorted array
  for (int v : sorta) 
  {
    System.out.println(v);
  }

  return median; 

   }

   public static int[] bubbleSort(int[] a)
    {
     //outer loop 
    for(int luck=0; luck<a.length -1; luck++){
     for (int juck=1; juck<a.length - luck; juck++){
       if (a[juck-1]>a[juck]){
         int temp= a[juck];
         a[juck]=a[juck-1];
         a[juck-1]=temp;
          //System.out.printf("unsorted array after %d pass %s: %n", luck+1,     Arrays.toString(a));
       }
      }
     }
    return a;
    }





 public static int calcMoe(int[] a)
{
    Arrays.sort(a);

     int count2 = 0;
     int count1 = 1;
     int pupular1 =0;
     int mode =0;


    for (int i = 0; i < a.length; i++)
    {
            pupular1 = a[i];
            count1 = 1;    

        for (int j = i + 1; j < a.length; j++)
        {
            if (pupular1 == a[j]) count1++;
        }

        if (count1 > count2)
        {
                mode = pupular1;
                count2 = count1;
        }

        if (count1 == count2)
        {
            mode = Math.min(mode, pupular1);

         }

         }


     return mode;
  }



public static int calcMax(int[] a) {
 //int min = a[0];
 int max = a[0];
  for (int i = 1; i <= a.length - 1; i++) {
  if (max < a[i]) {
   max = a[i];
   }
  }
   return max; 
}
public static int calcMin(int[] a) {
 int min = a[0];

  for (int i = 1; i <= a.length - 1; i++) {
  if (min > a[i]) {
   min = a[i];
  }
  }
   return min; 
}
public static double calcSd(int[] a) {
  //int sum = 0;
  //int max = 0;
  //int min = a[0];
  double sd = 0;
  int i = 0;
  double mean =0;
  sd=0;
    for ( i=0;i<a.length;i++)
        {
       sd += ((a[i] - mean)*(a[i] - mean)) / (a.length - 1);
    }  


 double standarddeviation = Math.sqrt(sd);
 {
 }
 return standarddeviation; 
 }
public static int calcQuart1(int[] a) {
  int[] sorta = bubbleSort(a);

  int q1 = 0;
  {
   int index = (sorta.length - 1) / 4;
   q1 = a[ index ] ;
  }


  for (int v : sorta) 
  {
    System.out.println(v);
  }

  return q1; 
 }
public static int calcQuart3(int[] a) {
  int[] sorta = bubbleSort(a);

  int q3 = 0;
  {
   int index = 3*(sorta.length - 1) / 4;
   q3 = a[ index ] ;
  }


  for (int v : sorta) 
   {
    System.out.println(v);
  }

  return q3; 
}
   public static double[] calcNumsum(int[] a) { 


  double median = calcMed (a);
  double max =calcMax (a);
  double min =calcMin (a);
  double q1=calcQuart1 (a); 
  double q3=calcQuart3 (a); 
  double[] vals = new double[5];
  vals[0] = min; 
  vals [1] = q1; 
  vals [2] = median; 
  vals [3] = q3; 
  vals [4] = max; 
  return vals;
}
   }

Answer 1

这一行：

System.out.println("5 number Summary:"+vals);

简单地获取 vals，将其转换为 String，然后打印出来。 Java 中数组类型的默认 toString 实现会产生您注意到的输出：整体类型（'array' 的 [），数组中存储的类型（D 表示 double），一个 @ 符号，以及数组在内存中的位置（在本例中为 689af4）。

为了获得对您的目的更有用的输出，您可以使用 Arrays.toString:

System.out.println("5 number summary: " + Arrays.toString(vals));

Answer 2

您的代码正在打印对象的内存位置 vals 而不是内容，要打印内容您必须像这样遍历它：

        System.out.println("5 number Summary:");
    for (double d : vals) {         
        System.out.print(d + ",");
    }

Answer 3

关于那个奇怪的输出 "5 number Summary:[D@689af4" 这只是数组的 reference ，这是数组的一般打印.如果要打印数组中的所有元素，则需要实现 toString 方法，基本方法是逐一打印数组中的元素。在您的情况下，它将是这样的：

System.out.print( "5 number Summary: ");
           for(int i = 0; i < vals.length; i++){
             System.out.print(" " + vals[i]); 
           }
           System.out.println();

平均模式方法的两个问题

two problems with mean med mode method

java

arrays

mode