物件導向設計:期末考觀念測試

Q1:
public class A
{
 public static void main(String args[])
 {  
  Data[ ]list = new Data[20];
  System.out.println(list[1].getnum());
//請問執行這行指令會有什麼結果?
//為什麼?
 }
}
class Data
{
  private static int num = 8;
  private char word;
  public int getnum()
  {
   return num;
  }
}


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Q2:
public class A
{
 public static void main(String args[])
 {  
             Data list = new Data();
             System.out.println(list.getword());
 }
}
class Data
{
  private char word = '1';


  public static char getword()
  {
   return word;
  }
}
//這程式是否產生任何錯誤訊息?
//若產生錯誤訊息，請解釋為何錯誤
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Q3:
public class A
{
public static void main(String args[])
{
             OuterClass D = new OuterClass("KK");
             InnerClass C = new InnerClass();
}
}

class OuterClass
{
        private String name ;
        public OuterClass (String name) 
        {
              this.name = name;    
              InnerClass inner = new InnerClass();
              inner.showName();
        }

        private class InnerClass 
        {
            public void showName ( )
            {
                  System.out.println ("Name = " + name) ;
            }
        }
}

//這程式何處出現錯誤?
//請試著描述原因。
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解答連結