Question

我试图在我的scores.txt文件中获得20个数字的平均值，但我无法弄清楚如何做到这一点。每次我尝试，我的输出都搞砸了。想法？

    public static void main(String[] args) throws IOException,
    FileNotFoundException {

    String file ="/Users/vienna01pd2016/Desktop/scores/src/scores/scores.txt";
    processFile("/Users/vienna01pd2016/Desktop/scores/src/scores/scores.txt");
    //calls method processFile
    }


    public static void processFile (String file)
    throws IOException, FileNotFoundException{
    String line;
    //lines is declared as a string


     BufferedReader inputReader =
       new BufferedReader (new InputStreamReader
(new FileInputStream(file)));

     while  (( line = inputReader.readLine()) != null){

      //System.out.println(line);
      double Value = Double.parseDouble(line);
     System.out.println(Value);

Answer 1

如果每行都有一个数字，我会使用BufferedReader读取每一行，将其放入列表并将其添加到数字中，然后您可以将总数除以列表中的数字量：

package Testers;

import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.FileReader;
import java.util.ArrayList;

public class MeanGetter {

    public static ArrayList<Double> ls = new ArrayList<Double>();

    public static void main(String[] args){
        String filepath = "/Users/vienna01pd2016/Desktop/scores/src/scores/scores.txt";
        double total = processFile(/*new File(filepath).getAbsolutePath()*/ filepath);
        double mean = total / ls.size();
        System.out.println("mean: " + mean);
    }

    private static double processFile(String path) {
        double n = 0;
        try {
            BufferedReader reader = new BufferedReader(new FileReader(new File(path)));
            String line;
            while  (( line = reader.readLine()) != null){
                double d = Double.parseDouble(line);
                n = n + d;
                ls.add(d);
            }
            reader.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return 0;


    }

}

添加使用BufferedReader读取的数字

1 个答案: