程序代码：

public class moon {

    /**
     * @param args
     */
    public static void main(String[] args) {
        Scanner input=new Scanner(System.in);
        // TODO Auto-generated method stub
        System.out.println("请输入数字：（0退出）");
        double a=input.nextDouble();
        
        double sum = a; //将a 的值赋给sum
        double avg = 0; 
        int num=0;
        
        
        while(a!=0){
            System.out.println("请输入数字：（0退出）");
            a=input.nextDouble();
            
            sum=sum+a;
            num++;    
        }
        if (num!=0)
            avg=(double)sum/num;
        System.out.println(num);
        
        System.out.println("总数："+sum);
        System.out.println("平均数："+avg);
        
    }

}