Java开发网 - 继承的问题

Topic: 继承的问题

1.继承的问题	Copy to clipboard
Posted by: czg4444 Posted on: 2006-09-05 11:56 class Jchen { short b=123; int c=1; long d=1234567890; float e=1.333f; double f= 1111.44d; } class JchenB extends Jchen{ public static void main(String args[]){ System.out.println(d+c); } } 请高人指教？？？？谢谢

2.Re:继承的问题 [Re: czg4444]	Copy to clipboard
Posted by: 熙城候 Posted on: 2006-09-05 13:42 没有在jchenb中声明 d,c这样编译好像过不了吧

3.Re:继承的问题 [Re: czg4444]	Copy to clipboard
Posted by: czg4444 Posted on: 2006-09-05 15:35 java.lang.NoSuchMethodError: main Exception in thread "main"

4.Re:继承的问题 [Re: czg4444]

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Posted by: JiafanZhou
Posted on: 2006-09-05 17:27

If you are very novice in learning Java, we can forgive you this question...It is so clear stated in the Java compiler that a non-static variable cannot be used in the static scope like a main method.

---------- Java Compiler ----------
JchenB.java:12: non-static variable d cannot be referenced from a static context
    System.out.println(d+c);
^
JchenB.java:12: non-static variable c cannot be referenced from a static context
    System.out.println(d+c);
^
2 errors

Output completed (1 sec consumed) - Normal Termination

1. try to change your source code like this:
class Jchen
{
  short b=123;
  int c=1;
  long d=1234567890;
  float e=1.333f;
  double f= 1111.44d;
}

class JchenB extends Jchen{
  public static void main(String args[]){
    Jchen test = new JchenB();
    System.out.println(test.d + test.c);
  }
}

2. Save your source code as JchenB.java because it contains your main method.

Notice the code indent because this is a Coding standard.

Kind regards
Jiafan

5.Re:继承的问题 [Re: czg4444]	Copy to clipboard
Posted by: leange Posted on: 2006-09-05 21:06 用super.d+super.c可以嘛？？为什么？

6.Re:继承的问题 [Re: czg4444]	Copy to clipboard
Posted by: lisliefor Posted on: 2006-09-05 22:16 super关键字，是调用父类的方法或变量！不过同样需要将d和c声明为static，或者你声明一个JChen的对象。

7.Re:继承的问题 [Re: czg4444]	Copy to clipboard
Posted by: czg4444 Posted on: 2006-09-07 13:59 大家好我刚学习到继承想做个实验就是建立两个类 A类建立一些参数让B类来调用，我的程序出现了上面的问题？？？请高人指教！！！！！！！！！！！！

8.Re:继承的问题 [Re: czg4444]	Copy to clipboard
Posted by: yzcj007 Posted on: 2006-09-07 17:07 变量为非static,不可直接使用 class Jchen { short b=123; static int c=1; static long d=1234567890; float e=1.333f; double f= 1111.44d; } class JchenB extends Jchen{ public static void main(String args[]){ System.out.println(d+c); } }