情急，请教，帮忙！__class_double_InnerOne_methoda_public_

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情急，请教，帮忙！

来源: 互联网发布时间：2015-10-12

本文导语: 这道题选什么？为什么这么选？ Given: public class OuterClass { private double d1 = 1.0; //insert code here } You need to insert an inner class declaration at line 3. Which two inner class declarations are valid?(Choose tw...

这道题选什么？为什么这么选？

Given:
public class OuterClass {
  private double d1 = 1.0;
    //insert code here
}
You need to insert an inner class declaration at line 3. Which two inner class declarations are valid?(Choose two.)

A:   class InnerOne{
  public static double methoda() {return d1;}
}
B:   public class InnerOne{
  static double methoda() {return d1;}
}
C:   private class InnerOne{
  double methoda() {return d1;}
}
D:   static class InnerOne{
  protected double methoda() {return d1;}
}
E:   abstract class InnerOne{
  public abstract double methoda();
}

我认为选c和e；
Inner Class 中的成员不能声明为 static；只有在顶层类中才可声明static；

选C
*************************************
Given:
public class OuterClass {
  private double d1 = 1.0;
    //insert code here
}
You need to insert an inner class declaration at line 3. Which two inner class declarations are valid?(Choose two.)

A:   class InnerOne{
  public static double methoda() {return d1;}//错！非静态内类不得拥有静态成员，除非是final的
}
B:   public class InnerOne{
  static double methoda() {return d1;}//错！理由同上
}
C:   private class InnerOne{
  double methoda() {return d1;}//ok，内类可以拥有private修饰
}
D:   static class InnerOne{
  protected double methoda() {return d1;}//错！静态内类无信封实例，看不到d1;
}
E:   abstract class InnerOne{
  public abstract double methoda();//感觉不对，无理由
}

***************************************

选A吧