java错误：AverageFINAL类中的构造函数AverageFINAL无法应用于给定类型；

Question

目标： 创建一个AverageDriver类。此类仅包含main方法。 main方法应该声明并实例化一个平均对象。平均数 然后应将对象信息打印到控制台

我在创建最后一段代码的对象部分时遇到了问题。我试着跟随我的课本，但仍然收到一条错误信息

import java.util.Scanner;

/**
 * The Average class calculates the average of the test 
 * scores entered and puts the scores into descending order.
 */

public class AverageFINAL
{
  private int[] data;


 public int calculateMean()
 {
   int total = 0;
   int mean;

    for (int index = 0; index < data.length; index++)
      total += data[index];
   mean = total / data.length;
   return mean;
 }

 public int selectionSort()
 {
   int startScan, index, minIndex, minValue;

    for (startScan = 0; startScan < (data.length-1); startScan++)
    {
      minIndex = startScan;
      minValue = data[startScan];
      for(index = startScan + 1; index < data.length; index++)
      {
        if (data[index] < minValue)
        {
          minValue = data[index];
          minIndex = index;
        }
      }
      data[minIndex] = data [startScan];
      data [startScan] = minValue;
    }
  return data[startScan];
 }
}

---

import java.util.Scanner;

public class AverageDriver
{
  public static int main(String[] args)
  {
   int[] data = new int[5];

   AverageFINAL object = new AverageFINAL(data);

   getValues(data);

   System.out.println("The test scores you entered, in descending order, are:");
   System.out.println(object.selectionSort());
   System.out.println("The average is" + object.calculateMean() +".");

  }

  private static int getValues(int[] data)
  {
  Scanner keyboard = new Scanner(System.in);
    for (int index = 0; index < data.length; index++) 
    {
      System.out.println("Enter score #" + (index + 1) + ": ");
      data[index] = keyboard.nextInt();
    }
  keyboard.close();
  }
}

我收到的错误消息是：

1 error found:
File: C:\Users\bryan\Downloads\AverageDriver.java  [line: 9]
Error: constructor AverageFINAL in class AverageFINAL cannot be applied to given types;
  required: no arguments
  found: int[]
  reason: actual and formal argument lists differ in length

Answer 1

在AverageFINAL中没有定义任何构造函数。在这种情况下，Java会创建一个默认的无参数构造函数

这就好像是被定义的：

public AverageFINAL() {}

但是，您试图在此行中传递int[]：

AverageFINAL object = new AverageFINAL(data);

如果要传递int[]，则必须显式创建一个构造函数，该构造函数将int[]作为其参数，并且可能希望将该int[]分配给实例变量data

Answer 2

在以下情况下使用时，需要一个带参数的构造函数：

AverageFINAL object = new AverageFINAL(data);

试试这个：

public class AverageFINAL
{
  private int[] data;
  public AverageFINAL(int[] dataParam) {
    data = dataParam;
  }
etc.