Question

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package javaapplication1;
 import java.io.*;
/**
 *
 * @author simon
 */
public class Main {


    /**
     * @param args the command line arguments
     */
       public static void main(String[] args) throws IOException {
            NotSimple[] objArray;
               BufferedReader stdin = new BufferedReader(
                                   new InputStreamReader( System.in ) );
            System.out.println( "Enter a number of objects:" );

            int size;
            size = Integer.parseInt( stdin.readLine() );

            //Initialize objArray
            objArray = new NotSimple[size];

            //TODO: Implement following functions

            initializeObj(objArray);
            increaseData(objArray);
            printObjData(objArray);

            //TODO: Explain all outputs of the below function
            explainOutputs();
            return;

                                                                 }

      //TODO
      //initialize every Notsimple object in the array 'a'
      //to NotSimple()
      //Hint: using the for loop, assign a[i] = new NotSimple();
      static void   initializeObj(NotSimple[] a){
      //TODO: FILL ME

          for (int i = 0; i < a.length; i++)
          {
          a[i] = new NotSimple();
          }

  }

  //TODO:
  //Increase the ‘data’ member of every NotSimple object
  //in the array ‘a’ by 1
  static void increaseData(NotSimple[] a) {
       //TODO: FILL ME

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

      }

  }

  //TODO:
  //Print the data of every NotSimple object in the array ‘a’
  static void printObjData(NotSimple[] a) {
       //TODO: FILL ME
       for (int i = 0; i < a.length; i++)
          {
          System.out.println (a[i].getData());
          }

  }

  //TODO explain all the outputs 1a-1f
  static void explainOutputs() {
    NotSimple nsObj1 = new NotSimple();
    //1a
    System.out.println( "nsObj1.data is\t" + nsObj1.getData() );
    System.out.println( "nsObj1.str is \t" + nsObj1.getStr() );

    NotSimple nsObj2 = new NotSimple( 50,
                         "Another immutable string!" );
    //1b
    System.out.println( "nsObj2.data is\t" + nsObj2.getData() );
    System.out.println( "nsObj2.str is \t" + nsObj2.getStr() );

    nsObj2 = nsObj1;

    nsObj2.setData(10);
    nsObj1.setData(100);
    //1c
    System.out.println( "nsObj2.data is\t" + nsObj2.getData() );
    System.out.println( "nsObj2.str is \t" + nsObj2.getStr() );

    nsObj1 = new NotSimple();
    //1d
    System.out.println( "nsObj1.data is\t" + nsObj1.getData() );
    System.out.println( "nsObj1.str is \t" + nsObj1.getStr() );
    System.out.println( "nsObj2.data is\t" + nsObj2.getData() );
    System.out.println( "nsObj2.str is \t" + nsObj2.getStr() );

    nsObj2 = new NotSimple();
    //1e
    System.out.println( "nsObj2.data is\t" + nsObj2.getData() );
    System.out.println( "nsObj2.str is \t" + nsObj2.getStr() );

    nsObj2.setData(10);
    //1f
    System.out.println( "nsObj1.data is\t" + nsObj1.getData() );
    System.out.println( "nsObj1.str is \t" + nsObj1.getStr() );
    System.out.println( "nsObj2.data is\t" + nsObj2.getData() );
    System.out.println( "nsObj2.str is \t" + nsObj2.getStr() );
  }

}


class NotSimple
{
  NotSimple()
  {
    data = 5;
    str = new String( "Initialized!" );
  }

  NotSimple( int i, String str1 )
  {
    data = i;
    str = str1;
  }

  void setData( int i )
  {
    data = i;

    return;
  }

  int getData()
  {
   return data;
  }

  void setStr( String str1)
  {
    str = str1;

    return;
  }

  String getStr()
  {
    return str;
  }

  private int data;
  private String str;
}

教师要我“将数组'a'中每个NotSimple对象的'data'成员增加1”当我运行程序时，它只会增加第一个数据。例如，当我输入3时，我得到了这个：

运行：

Enter a number of objects:
3
6
6
6
nsObj1.data is        5
nsObj1.str is         Initialized!
nsObj2.data is        50
nsObj2.str is         Another immutable string!
nsObj2.data is        100
nsObj2.str is         Initialized!
nsObj1.data is        5
nsObj1.str is         Initialized!
nsObj2.data is        100
nsObj2.str is         Initialized!
nsObj2.data is        5
nsObj2.str is         Initialized!
nsObj1.data is        5
nsObj1.str is         Initialized!
nsObj2.data is        10

我的问题是不应该将所有数据增加1吗？即101,6,101,6,6,11

Answer 1

这里有两个主要操作。第一个是创建包含x个元素的数组，每个元素都使用值5进行初始化并增加1。这给你这个结果：

3
  6
  6
  6

3个元素，值为5，递增。

代码的第二部分（explainOutputs()）不会增加任何内容。声明了两个对象（nsObj1和nsObj2），并在打印它们之前手动修改它们。没有增量。它只打印您设置的内容。

以下是您的所作所为：

NotSimple nsObj1 = new NotSimple();
打印5。
NotSimple nsObj2 = new NotSimple(50, "Another immutable string!");
打印50
nsObj2 = nsObj1; nsObj2.setData(10); nsObj1.setData(100); 基本上你只是说nsObj2值是100并且它打印100
nsObj1 = new NotSimple();
nsObj1将打印5（因为它是对新对象的引用）
nsObj2仍将打印100
nsObj2 = new NotSimple();
nsObj2是对新Object的引用，它将打印5
nsObj2.setData(10);
nsObj1仍然打印5
nsObj2将打印10，因为只有nsObj2引用的对象将更改值

结果： 5 50 100 5 100 5 5 10

Answer 2

仅在increaseData上调用data方法，该方法增加其参数数组中对象的成员字段objArray。

在方法explainOutputs中，您不会在任何地方增加。您将data字段设置为不同的值并打印它们。

要解决此问题，您可以编写另一个需要increaseData的重载NotSimple方法：

static void increaseData(NotSimple a) {
    a.setData(a.getData()+1);
}

在打印explainOutputs方法中的任何对象之前调用此方法：

NotSimple nsObj1 = new NotSimple();
//1a
increaseData(obj1); // ADD THIS.
System.out.println( "nsObj1.data is\t" + nsObj1.getData() );
System.out.println( "nsObj1.str is \t" + nsObj1.getStr() );

使用上面的方法，您现有的increaseData方法可以将其用作：

static void increaseData(NotSimple[] a) {
   for (int i = 0; i < a.length; i++) {
        increaseData(a[i]); // call increaseData for each object in the array.
   }
}

我坚持我的任务，我可以得到一些反馈吗？ java的

2 个答案: