Question

我被困在这项任务中。它是关于从用户输入的文本文件中取一些等级而不是计算max，min，mean。问题是我每次尝试编译它都会给我这个

St.java:10: readfile(int[],java.lang.String) in St cannot be applied to (int[])
int n = readfile (grades);

源代码：

import java.io.*;

import java.util.Scanner;

public class St

{

    public static void main ( String [] a )

    {

        Scanner kbd = new Scanner(System.in);

        int count = 0;
        int [] grades = new int [500];
        int n = readfile (grades);

        System.out.println("What file contains the data?");

        String file = kbd.nextLine();

        System.out.println("The maximum grade is: " + max(grades,n));
        System.out.println("The minimum grade is: " + min(grades,n));
        System.out.println("The mean grade is: "+ mean(grades,n));

        }
    public static double mean(int [] grades,int n)
    {
        double sum = 0;
        for(int i = 0; i < n; i++)
        {
            sum = sum + grades[i];
        }
        return sum/n;
    }

    public static int readfile (int [] grades, String file)
    {
        int count = 0;
        try
        {
            Scanner f = new Scanner (new File (file)); // name of file
            while (f.hasNext()) // checks if there is more input in the file
            {
                grades[count]=f.nextInt (); // grabs the next piece of input
                count++; // moves onto the next piece of input (increasing count)

            }
        }
        catch (IOException e)
        {
            System.err.println (e);
            System.exit(0);
        }
        return count;


    }
    public static void writeArray (int [] grades , int n)
    {
        for (int i = 0; i < n; i++)
        {
            System.out.println (grades[i]);
        }
    }   
    public static int max(int [] y,int m)
    {
        int mx = 0;
        for(int i = 0; i < m; i++)
        {
            if(y[i] > mx)
            {
                mx = y[i];
            }
        }
        return mx;
    }

    public static int min(int [] grades,int n)
    {
        int mn = 0;

        for(int i = 0; i < n; i++)
        {
            if(grades[i] < mn)
            {
                mn = grades[i];
            }
        }
        return mn;
    }

}

Answer 1

你正试图通过

int n = readfile (grades);

但是您创建的功能：

public static int readfile (int [] grades, String file)

要求第二个变量作为String

你需要改变你的行：

String fileName= YOUR_FILE_NAME;
int n = readfile (grades,fileName);

Answer 2

您没有使用从用户那里获得的输入文件名。

改变这个：

int n = readfile (grades);
System.out.println("What file contains the data?");
String file = kbd.nextLine();

到

System.out.println("What file contains the data?");
String file = kbd.nextLine();
int n = readfile (grades, file);

因此，您从用户处获取文件名并将其传递给您的方法。

从文本文件中计算成绩

2 个答案: