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用Java中的扫描仪读取文件_Java_File - Fatal编程技术网

用Java中的扫描仪读取文件

用Java中的扫描仪读取文件,java,file,Java,File,在本作业中,我们假设从txt文件中读取测试和家庭作业分数,并计算最终分数。由于我们尚未了解如何读取和写入文件,这是提供给我们的预制方法: /****************************************************************************** * * Filename : GradeCalculatorFromFile.java. * Author: xxxxxxxxx * Date: 09/0

在本作业中,我们假设从txt文件中读取测试和家庭作业分数,并计算最终分数。由于我们尚未了解如何读取和写入文件,这是提供给我们的预制方法:

/******************************************************************************
 *
 * Filename :     GradeCalculatorFromFile.java.
 * Author:        xxxxxxxxx
 * Date:          09/025/2011
 * Description:  This program computes the scores of a list of students in the CSE155a class
 *
 ******************************************************************************/
import java.io.File;
import java.io.FileNotFoundException;
import java.util.*;

/* Provide a description of the class */
public class GradeCalculatorFromFile {
    public static void main(String[] args) {
        // Declare and initialise the variables as needed
        int anthonyHopkinsTest = 0;
        int anthonyHopkinsHomework = 0;

        /*
         * The following code enables the user to accept input from the
         * keyboard. Keep this code as it is.
         */
        Scanner scanner = null;
        try {
            scanner = new Scanner(new File("grades.txt"));
        } catch (FileNotFoundException e) {
            System.out.println("Error opening file. Please make sure that you have a grades.txt file in the same folder as GradeCalculator.class");
            System.exit(0);
        }

        /*
         * Add your code here to read the number of students and the scores Use
         * scanner.next() to read a String Use scanner.nextInt() to read an int
         */
    }
}
这是我们打算使用的txt文件:

4
Anthony Hopkins 80  90  95  87  80  78  25  17  20  22  21  24  19  22  21  23  24  21  20  25  20  55  56  110 30  20  25  8
John    Smith   99  95  82  72  64  52  15  14  11  21  25  12  19  20  21  23  21  12  12  10  15  50  50  60  25  15  20  9
Pan     Mei     85  92  72  45  82  78  22  13  16  22  24  10  18  12  21  24  25  10  11  14  20  58  51  95  28  14  28  7
Rafael  Vega    99  45  87  52  87  99  25  25  21  21  14  19  19  25  25  20  20  18  20  24  20  60  60  60  25  16  23  8

问题是我们没有被教会如何从文件中获取信息。说明书上说要用扫描仪来评分,但我不知道怎么做。小组中的前21个数字是家庭作业,下3个是测试,最后4个是家庭作业。我知道如何用用户输入来做这类事情,但在从文件读取信息时却不知道。从文件读取信息与从用户输入读取信息是一样的?然后某种形式的for循环添加到他的分数上?试试看会发生什么。我试过:
anthonyHopkinsTest=scanner.nextInt();对于(inti=1;i<7;i++){System.out.println(anthonyHopkinsTest);}
,多次得到4。我把它读了,这很酷。如何选择要读取的行?请检查java文档中的扫描仪。