java如何在数组中显示等级？

Question

教授的样本输出：

到目前为止，我的代码是：

import java.util.*;
import java.io.*;
import java.text. DecimalFormat;
public class HW10 {
    public static void main(String[] args) throws IOException {

        System.out.println("Which file would you like to read?");

        Scanner keyboard = new Scanner(System.in);
        String name = keyboard.next();
        Scanner reader = new Scanner(new File(name));

        double numbers[][] = new double[reader.nextInt()+1][reader.nextInt()+1]; //+1 for averages

        //loop over all the rows
        for (int i=0; i<numbers.length; i++) { 
            //loop over all the columns in row i
            for (int j=0; j<numbers[i].length; j++) { 
                //this code will execute on each and every cell row i, column j
                numbers[i][j] = reader.nextDouble();
            }
            double sum = 0;
            double average = (sum/(numbers.length));
        }
        //loop over all the rows
        for (int i = 0; i<numbers.length-1; i++) { 
            System.out.println("Assignment #: ");
            System.out.println("array 1, 2, 3, 4, 5, 6, Avg");
            System.out.println("Student 1: ");
            System.out.println("Student 2: ");
            System.out.println("Student 3: ");
            System.out.println("Student 4: ");
            System.out.println("Student 5: ");
            System.out.println("Average: ");

            for (int j=0; j<numbers[i].length-1; j++) { //loop over all the columns in row i
                System.out.print(numbers[i][j] + " "); //print out the cell value and then a space
            }
            //System.out.println("The overall class average is " + (totalResults/(numbers.length))); //the class average
            DecimalFormat numPattern = new DecimalFormat("##.#");
        }
        //overall average code here
    }
}

为了正确显示所有内容，需要显示数组，以便标题和打印行都有意义。为此，我在不了解如何显示数据的地方放置了一些占位符

虽然上面的代码已经编译好了，但是当分数出现时，它给了我一个异常错误。输入txt文件作为名称——工作目录包含该文件，所以我也不确定为什么它在程序中没有移动过去

我想，如果我能克服这个障碍，我将能够很好地显示数组，但我寻求堆栈对我的代码语法外观的建议。有什么改进意见吗

Answer 1

你可以使用String.format()

System.out.print(String.format("%10s", numbers[i][j]+""));

你可以试试看

  System.out.println(String.format("%50s","Assignment #: "));
  System.out.println(String.format("%10s%10s%10s%10s%10s%10s%10s%10s","array", "1", "2", "3", "4", "5", "6", "Avg"));
  System.out.println(String.format("%10s","Student 1: "));
  System.out.println(String.format("%10s","Student 2: "));
  System.out.println(String.format("%10s","Student 3: "));
  System.out.println(String.format("%10s","Student 4: "));
  System.out.println(String.format("%10s","Student 5: "));
  System.out.println(String.format("%10s","Student 6: "));

顺便说一句，我认为你打印表格的for循环是错误的
在代码中，“赋值#：：”和“数组1，2，3，4，5，6，Avg”将重复
此外，在开始新的一行之前，你应该打印学生的分数

打印标记的for循环的伪代码：

print "Assignment #:"
print " array 1, 2, 3, 4, 5, 6, Avg "
for i= 1-5 //rows
    print "Student " + i
    for j= 1-6 //column
        print score of assignment j of student i
    end for
    print avg
end for
print "Overall Average" + overallAverage

Answer 2

使用\t在文本中放置制表符

System.out.println("\t\t1\t2\t3\t4\t5\t6\tAvg");

将输出：

          1    2    3    4    5    6    Avg

您还可以添加一个焊盘：

public static void main(String args[]) throws Exception {
 System.out.println(padRight("Howto", 20) + "*");
 System.out.println(padLeft("Howto", 20) + "*");
}
/*
  output :
     Howto               *
                    Howto*
*/

Check this question了解有关填充的更多信息String

提示：为了获得结果，你必须打印每行的所有信息，并将其排成一行或将每个学生的信息放在一个变量中，并在最后打印出来

Check this answer知道如何操作String和使用StringBuilder

Answer 3

要格式化输出，请使用String.format().

System.out.println(String.format("%4d", 5));// for int
System.out.println(String.format("%-20s= %s" , "label", "content" ));//for string

在哪里

%s is a placeholder for you string.

The '-' makes the result left-justified.

20 is the width of the first string

see link

另一个问题是关于文件打开的问题

只给出文件名没有帮助。试着给出整条路

使用System.getProperty("user.dir");获取路径

String name = keyboard.next();
String path = System.getProperty("user.dir");
Scanner reader = new Scanner(new File(path + " \\ " + name));