传递字符串的ArrayList的方法返回一个double值

Question

我工作的分配问题，其即时通讯停留在：

我提取的文本文件grades.txt到所谓的一个ArrayList studentgrade 我想接着使用提取到arraylist的等级来转换等级。

转换等级的目的是读取文本文件的行，然后将字符串值转换为点;然后将所有等级总和点加起来。

package Q2; 
import java.util.StringTokenizer; 
import java.util.ArrayList; 
import java.io.File; 
import java.io.FileNotFoundException; 
import java.io.IOException; 
import java.util.Scanner; 
import java.util.List; 

public class studentGPA { 

private static String studentGrades[]; 

public static void main(String[] args) throws IOException { 
    double gpa, points = 0;  
    //opening grades and extracting to array 

    File file = new File ("Grades.txt"); 
    Scanner inputFile = new Scanner(file); 

    ArrayList<String> studentlist = new ArrayList<String>(); 

      while (inputFile.hasNext()) 
      { 
       studentlist.add(inputFile.nextLine()); 
      } 

/*print out student ID 

    for (int index = 0; index<studentlist.size(); index++) 
    { 
     StudentID = (studentlist.get(index)).split(" ",11); 
     System.out.println("studentID:" + index + ": " + StudentID[0]); 

    } 
    System.out.println(); */ 



      studentGrades = null; 

    for (int index = 0; index<studentlist.size(); index++) 
    { 
     String data[] = studentlist.get(index).split(" "); 
     for (int index_grade = 0 ; index_grade < 8;) 
     { 
      studentGrades[index_grade] = data[index_grade+3]; 
     } 
     System.out.println(convertGrade(studentGrades)); 

    } 

    //testing purposes 
    /*for (int index = 0; index<studentlist.size(); index++) 
    { 
     StudentGrade = (studentlist.get(index)).split(" ",11); 


     System.out.println("studentID:" + index + ": " + StudentGrade[3] + StudentGrade[4] + 
       StudentGrade[5] + StudentGrade[6] + StudentGrade[7] + StudentGrade[8] + StudentGrade[9]); 
    }*/ 




    //answer should be 46 but im getting 14 


} 

public static double convertGrade(String studentgrade[]) { 
     double points = 0; 

     for (int index = 3; index<studentgrade.length; index++) 
     { 
     if (studentgrade[index].contains("H")) 
      points = 7; 
     else if (studentgrade[index].contains("D")) 
      points = 6; 
     else if (studentgrade[index].contains("C")) 
      points = 5; 
     else if (studentgrade[index].contains("P")) 
      points = 4; 
     else if (studentgrade[index].contains("F")) 
      points = 0; 
     points = points + points; 
     } 
     return points; 
    } 


} 

• 57363乔伊莱德DDCPHHCD ==== 6 + 6 5 4 + 7 + 7 5 + 6 = 46
• 72992劳拉Norder HHHDDHHH
  • 71258艾琳超过CFCDCCCP

编辑：

Answer 1

你必须做这样的：

System.out.println(convertGrade(StudentGrade)); 

编辑

for (int index = 0; index<studentlist.size(); index++) 
{ 
    String data[] = studentlist.get(index).split(" "); 
    for (int index_grade = 0 ; index_grade < 8) 
    { 
     StudentGrade[index_grade] = data[index_grade+3]; 
    } 
    System.out.println(convertGrade(StudentGrade)); 
}