import java.io.*;

public class ScoreCalculate {
    public static void main(String[] args){
        String filename="w7/Scores.txt";
        int sum=0;
        int count=0;
        try(BufferedReader br=new BufferedReader(new FileReader(filename))){
            String line;
            while((line=br.readLine())!=null){
                line=line.trim();
                if(line.isEmpty()){
                    continue;
                }
                sum+=Integer.parseInt(line);
                count++;
            }
            if(count>0){
                double average=(double)sum/count;
                System.out.println("平均分为"+average);
            }
            else{
                System.out.println("无有效成绩");
            }
        }
        catch(FileNotFoundException e){
            System.out.println("文件未找到或不存在:"+e.getMessage());
        }
        catch(IOException e){
            System.out.println("文件读取错误:"+e.getMessage());
        }
        catch(NumberFormatException e){
            System.out.print("文件中包含无法解析为数字的内容:"+e.getMessage());
        }
    }
}