题目是：求平均数，用户循环输入任意个非0的数，输入0退出循环，系统计算并显示这些数的平均值。

我写的是
import java.util.*;
public class avg {
    public static void main(String[] args) {
        boolean con;
        int i=0;
        double num;
        double sum=0;
        double avg;
        do {
            Scanner input=new Scanner(System.in);
            System.out.print("请输入数字：");
            num=input.nextInt();
                           con=num==0;
                           sum=sum+num;
                           i++;
        }while(!con);
        avg=sum/i;
        System.out.println("\n共输入"+i+"个数字，和是"+sum+",平均数是"+avg);
    }
}
不知道哪里有问题呢
我是新手，大家帮忙改下

那个0应该只是一个开关数字吧?

import java.util.*;
public class avg {
    public static void main(String[] args) {
        boolean con;
        int i=0;
        double num;
        double sum=0;
        double avg;
        do {
            Scanner input=new Scanner(System.in);
            System.out.print("请输入数字：");
            num=input.nextInt();
                           //con=num==0;
                           sum=sum+num;
            if(con=num==0)
            {
                System.out.println("你输入的有效数字是:"+i+"个");
            }
            i++;
        }while(!con);
        avg=sum/(i-1);
        System.out.println("和是"+sum+"\n"+"平均数是"+avg);
    }
}

import
import
import

public class avg
{
    public static void main(String[] args) throws IOException
    {
        BufferedReader buf = new BufferedReader(new InputStreamReader(System.in));
        String str;
        int i = 0;
        double num;
        double sum = 0;
        double avg;        
        do
        {
            System.out.print("请输入数字：");            
            str=buf.readLine();                        
            try
            {
                num = Double.parseDouble(str);
            }
            catch(NumberFormatException  e)//捕获异常时跳出
            {
                break;
            }            
            sum += num;
            i++;
        } while (true);
        avg = sum / i;
        System.out.println("\n共输入" + i + "个数字，和是" + sum + ",平均数是" + avg);
    }
}

哦，明白了

4楼的好些语句我都不懂，应该是很没学到吧！！

遇到不懂的类,多查查API帮助,看多了自然就懂了的.呵呵~~~

API帮助是不是要另外装啊，在网上下吗

是文档,在网上下载得了.