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我的任务是计算用户在数组中定义的整数的平均值，并使用我的类文件中的方法打印回 main。

目前我有两个文件要编译，但似乎无法弄清楚为什么什么都没有打印。请帮忙，不胜感激！

测试程序中要检查的代码片段：

// Print average of integers in array.
     System.out.println("\nAverage of values in array =");
     myArray.avgArray();

类程序中要检查的代码片段：

// Method to calculate average of integers in array.
  public double avgArray()
  { 
     int sum = 0;

     for(int ctr = 0; ctr < limit; ctr++)
     {
       sum = sum + nrs[ctr];
     }

     double avg = sum /(double)limit;

     return avg;
  }

这段代码是我用于测试目的的程序：

import java.util.Scanner;


public class P5test
{
  public static void main(String[] args)
  {
    // Set up Scanner object for keyboard input.
     Scanner keyboard = new Scanner(System.in);

     // Input size of array desired.
     System.out.print("Size of array:   ");
     int size = keyboard.nextInt();

     // Set up object.
     P5class myArray = new P5class(size);

     // Allow user to fill array.
     System.out.println("\nEnter data for array:");
     myArray.fillArray();

     // Print contents of array.
     System.out.println("\nContents of array:");
     myArray.printArray();

     // Print average of integers in array.
     System.out.println("\nAverage of values in array =");
     myArray.avgArray();

     // Print postive values in array.
     System.out.println("\nPositive values in array:");
     myArray.pvaluesArray();

     // Sort contents of array in ascending order.
     System.out.println("\nSorted Array:");
     myArray.sortArray();
     myArray.printArray();
  }
}

这段代码包含我的类以及我将在 main 中实现的各种方法：

import java.util.Scanner;

public class P5class
{
  // Constructor setting up empty array of size specified by user.
  public P5class(int size)
  {
    limit = size;
     nrs = new int[limit];
  }

  // Method to fill array.
  public void fillArray()
  {
    // Set up Scanner object for keyboard input.
     Scanner keyboard = new Scanner(System.in);

     for(int ctr = 0; ctr < limit; ctr++)
     {
       System.out.print("Integer #" + (ctr+1) + ":  ");
        nrs[ctr] = keyboard.nextInt();
     }
  }

  // Method to display contents of array.
  public void printArray()
  {
    for(int ctr = 0; ctr < limit; ctr++)
     {
       System.out.println("Nrs[" + ctr + "] = " + nrs[ctr]);
     }
  }

  // Method to calculate average of integers in array.
  public double avgArray()
  { 
     int sum = 0;

     for(int ctr = 0; ctr < limit; ctr++)
     {
       sum = sum + nrs[ctr];
     }

     double avg = sum /(double)limit;

     return avg;
  }

  // Method to examine if any positive values are present in array.
  public void pvaluesArray()
  {
    int largest = nrs[0];

    // Check to see if any other number in array is larger than first.
    for(int ctr = 1; ctr < limit; ctr++)
    {
      if(nrs[ctr] > largest)
         largest = nrs[ctr];
    }

    int sum = 0;

    for(int ctr = 0; ctr < limit; ctr++)
    {
      sum = sum + nrs[ctr];
    }

    double average = (double)sum/limit;


    for(int ctr = 0; ctr < limit; ctr++)
    {
      if(largest <= 0)
      {
        System.out.println("\nArray contains no positive integers.");
          break;
      }
      else if (nrs[ctr] > 0)
      {
        System.out.println("Nrs[" + ctr + "] = " + nrs[ctr]);
      }
    }
  }

  // Method to sort array into ascending order.
  public void sortArray()
  {
    for(int ctr0 = 0; ctr0 < limit-1; ctr0++)
     {
       // Make one pass of Bubble Sort.
       for(int ctr = 0; ctr < limit-1; ctr++)
       {
         if(nrs[ctr] > nrs[ctr+1])
          {
            int temp = nrs[ctr];
            nrs[ctr] = nrs[ctr+1];
            nrs[ctr+1] = temp;
          } 
       }
     }
  }

  // Instance variables.
  private int limit;
  private int[] nrs;
}

这是运行时程序的示例输出：

 ----jGRASP exec: java P5test

Size of array:   5

Enter data for array:
Integer #1:  0
Integer #2:  -9
Integer #3:  4
Integer #4:  7
Integer #5:  2

Contents of array:
Nrs[0] = 0
Nrs[1] = -9
Nrs[2] = 4
Nrs[3] = 7
Nrs[4] = 2

Average of values in array =

Positive values in array:
Nrs[2] = 4
Nrs[3] = 7
Nrs[4] = 2

Sorted Array:
Nrs[0] = -9
Nrs[1] = 0
Nrs[2] = 2
Nrs[3] = 4
Nrs[4] = 7

 ----jGRASP: operation complete.
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1 回答 1

3

它返回一个值，但你没有用它做任何事情，试试：

System.out.println("\nAverage of values in array = " + myArray.avgArray());

或者：

double avg = myArray.avgArray();
System.out.println("\nAverage of values in array = " + avg);

或许多其他方式之一。

或者，return avg;您可以简单地在方法中将其打印出来，而不是 ，System.out.println(avg);并将返回类型更改为void。

于 2013-04-17T15:40:55.083 回答