Java开发网 - 新手一段代码编译错误求助 ('class' or 'interface' expected)

Topic: 新手一段代码编译错误求助 ('class' or 'interface' expected)

1.新手一段代码编译错误求助 ('class' or 'interface' expected)

Posted by: zxhhero
Posted on: 2004-10-19 20:59

下面一段代码在编译时报错，我以前也引入过“java.util.*"没有错误，在这里请问是什么问题？如何解决？感谢先！！

public class Cat{
  private int catNumber;
  Cat(int i){catNumber=i;}
  void print(){ System.out.println("Cat#"+catNumber);}

}

public class Dog{
  private int dogNumber;
  Dog(int i){dogNumber=i;}
  void print(){ System.out.println("Dog#"+dogNumber);}
  }


import java.util.* ;

public class CatsAndDogs{
  public static void main(String[] args){
    ArrayList cats=new ArrayList();
    for (int i=0;i<7;i++)
     cats.add(new Cat(i));
     cats.add(new Dog(7));
     for(int i=0;i<cats.size();i++)
     ((Cat)cats.get(i)).print();

  }
}

2.Re:新手一段代码编译错误求助 [Re: zxhhero]	Copy to clipboard
Posted by: helloworld Posted on: 2004-10-19 21:05 把上面的两个类,移到程序尾巴上.

3.Re:新手一段代码编译错误求助 [Re: zxhhero]	Copy to clipboard
Posted by: zxhhero Posted on: 2004-10-19 21:34 楼上的大哥，好像不行！

4.Re:新手一段代码编译错误求助 [Re: helloworld]	Copy to clipboard
Posted by: why Posted on: 2004-10-19 22:43 helloworld wrote: 把上面的两个类,移到程序尾巴上. They are public classes! One needs to have 3 java files: Cat.java, Dog.java, and CatsAndDogs.java OR make Cat and Dog non-public and 把上面的两个类,移到程序尾巴上

5.Re:新手一段代码编译错误求助 ('class' or 'interface' expected) [Re: zxhhero]	Copy to clipboard
Posted by: yclc Posted on: 2004-10-20 10:52 3个人都要当主人，当然会吵架了

6.Re:新手一段代码编译错误求助 ('class' or 'interface' expected) [Re: zxhhero]	Copy to clipboard
Posted by: kulatasana Posted on: 2004-10-20 23:14 把上面的Dog和Cat类移到CatsAndAodgs类里做内部类就好

7.Re:新手一段代码编译错误求助 ('class' or 'interface' expected) [Re: zxhhero]	Copy to clipboard
Posted by: kavinwang Posted on: 2004-10-21 09:50 ((Cat)cats.get).print();这一句猫狗不分，强把狗变成猫，肯定有问题。你应该把Cat和Dog继承同一个类或实现同一个接口，比如: public interface A{ public void print(); } 然后改：((Cat)cats.get).print();到((A)cats.get).print();

8.Re:新手一段代码编译错误求助 ('class' or 'interface' expected) [Re: zxhhero]	Copy to clipboard
Posted by: wddodo Posted on: 2004-10-21 10:43 楼上说的有道理。

9.Re:新手一段代码编译错误求助 ('class' or 'interface' expected) [Re: zxhhero]	Copy to clipboard
Posted by: eric_dasini Posted on: 2004-10-21 17:27 把 Cat 和 Dog class前面的 public 去掉！每个java源文件中只能有一个class 被声明为public的！！这个class 的名字要和文件名同名！！！

10.Re:新手一段代码编译错误求助 ('class' or 'interface' expected) [Re: eric_dasini]	Copy to clipboard
Posted by: kavinwang Posted on: 2004-10-21 18:46 eric_dasini wrote: 把 Cat 和 Dog class前面的 public 去掉！每个java源文件中只能有一个class 被声明为public的！！这个class 的名字要和文件名同名！！！子类也可以声明为public的

Topic: 新手 一段代码编译错误求助 ('class' or 'interface' expected)

Topic: 新手一段代码编译错误求助 ('class' or 'interface' expected)