java扫描仪数据多种类型

Question

过去 3 小时我一直在做家庭作业，但没有取得太大进展。我想知道是否有人可以帮助我走向正确的方向。

任务是从文件中读取数据并将其转换为对读者更友好的内容。数据文件看起来像这样:

0.30 0.30 0.40

161

3333 70 60 50

4444 50 50 50

5555 80 90 80

0

162

1212 90 85 92

6666 60 80 90

7777 90 90 90

8888 95 87 93

9999 75 77 73

0

263

2222 90 65 75

8989 60 40 60

9090 70 80 30

0

该文件包含 5 种不同类型的数字。
1. 三位数为类(class)编号。
2. 四位数字是学号。

这两位数字是每个学生的作业、期中和期末成绩。

顶部的小数用于计算分数的加权平均值。

零是类(class)之间的休息时间。

我应该读取文件中的所有数据，然后格式化并输出它，以便于阅读:

Grade Data For Class 161

 ID   Programs  Midterm  Final  Weighted Average  Programs grade
 --   --------  -------  -----  ----------------  --------------
3333     70       60      50         59.00        Pass
4444     50       50      50         50.00        Fail
5555     80       90      80         83.00        Pass
Class Average:  64.00

我有扫描仪设置，并且能够从文本中解析出数字，我的问题是它们都保存为字符串，所以我无法对它们进行任何数学检查。我开始怀疑这是否是解决这个问题的最佳方法。

import java.util.Scanner;
import java.io.File;
import java.io.IOException;

public class classAverage
{
    public static void main(String[] args) throws IOException
    {
        //in variable equals entire file
        Scanner in = new Scanner(new File("courseData.txt"));

        int classID;



        System.out.println("ID  Programs  Midterm  Final  Weighted Average  Programs Grade");
        System.out.println("--  --------  -------  -----  ----------------  --------------");

        while(in.hasNextLine())   //While file has new lines
        {
            //line equals each line of text
            String line = in.nextLine();
            Scanner lineParser = new Scanner(line);
            System.out.println(line);

            for(; lineParser.hasNext();)
            {
                //number = each number
                String number = lineParser.next();
                System.out.println(number);



                if(number < 1 && number > 0)
                {
                    double programsAverage = number.nextDouble();
                    double midtermAverage = number.nextDouble();
                    double finalAverage = number.nextDouble();
                    System.out.println(programsAverage);
                    System.out.println(midtermAverage);
                    System.out.println(finalAverage);

                }

            }

        }



    }

}

更新 我已包含更新的代码。我现在的问题是我的 for 语句中的条件。这些应该检查传入扫描仪数据的值以查看数据是否:

• a weight calculator(0,1)
• a score(1,100),
• a classNumber (100,400),
• a studentNumber(1000,9999),
• a class separator (0).

我在想这样的事情:

for(in.next(); in < 100 && in > 1; next());

但这并没有完全做到这一点。

import java.util.Scanner;
import java.io.File;
import java.io.IOException;

/**
 * Write a description of class classAverage here.
 * 
 * @author 
 * @version 
 */
public class classAverage
{
    public static void main(String[] args) throws IOException
    {
        //in variable equals entire file
        Scanner in = new Scanner(new File("courseData.txt"));

        int classNumber;
        int studentNumber;
        int programs;
        int midterm;
        int finals;


        double programWeight = in.nextDouble();
        double midtermWeight = in.nextDouble();
        double finalWeight = in.nextDouble();

        //System.out.println(programWeight +  " " + midtermWeight + " " + finalWeight);
        for(int k = 0; k < 3; k++)
        {
            for(int i = 0; i <= 0; i++)
            {
                classNumber = in.nextInt();

                System.out.println("Grades for class: " + classNumber);
                System.out.println(" ID    Programs  Midterm  Final  Weighted Average  Programs Grade");
                System.out.println(" --    --------  -------  -----  ----------------  --------------");
            }

            int studentCount = 0;
            double sumAverage = 0.0;

            for(int j = 0; j <= 2; j++)
            {
                studentNumber = in.nextInt();
                programs = in.nextInt();
                midterm = in.nextInt();
                finals = in.nextInt();
                studentCount++;
                double weightedAverage = (programWeight * programs) + (midtermWeight * midterm) + (finalWeight * finals);
                sumAverage += weightedAverage;

                System.out.printf("%d      %d        %d      %d        %.2f          ", studentNumber,programs,midterm,finals,weightedAverage);
                if(programs >= 70)
                {
                    System.out.print("PASS");
                } else {
                    System.out.print("FAIL");
                }
                System.out.println();
            }
            double classAverage = sumAverage / studentCount;
            System.out.printf("Class average is: %.2f", classAverage); 
            System.out.println("\n\n");

        }



    }

}

Answer 1

这里有 2 个选择:

1. Use Scanner#hasNextInt() and nextInt() instead of nextLine() to read Integers directly instead of numbers in String format.

2. Keep your reading / scanning code intact. Use Integer.parseInt() to convert String to Integers. --> Preferred solution. As it is more efficient.