Wsrtjtyk

I have a text file which includes student names an grades. I am trying to read the grades and put them into a 2d array in a separate method, then I want to call it in the main method to print out the array. However, if I debug my code in its own method, I get everything print out, but if I call it in the main method, then only the last row of the array got printed out. Can you guys please tell me what am I missing here?

Thanks a lot for all your help.

This is my text file:

John  25 5 4.5 5 4 5 10 10 6 9.5 5.5

Jim   25 5 4 5 4.5 5 10 4 10 9.5 7.5

Kathy 15 1 3 2 1 1.5 8 2 4 3 4

Steve 21 5 3 2 1 4 5 6 7 8 8

Stacy 15 5 1 1 1 5 3 8 9 5 7

Faith 16 3 4 2 4 4 7 5 2 3 8

This is my method

    public static double processGrades(double grade) throws IOException 

{       

    PrintWriter writer = new PrintWriter(new FileOutputStream("Output.txt"));



        Scanner readNum = null;

        Scanner scan =  null;

        int count = 0;

        int count2 = 0;   

        int width = 0;              

        String col = null;                

        String tempGrade = null; 

        String line = null;

        String line2 = null;

        String newline = null;

        int maxInLine = 0;



        try

        {           

             //Create Grades Array



             scan = new Scanner(new FileInputStream("input.txt"));



             scan.nextLine();



             while(scan.hasNext())

             {

                line2 = scan.nextLine();    

                col = line2.split(" ");

                width = col.length;

                count++;    



                System.out.println(col.length);

             }



             tempGrade = new String[count][width];          

             grade = new double[count][width];



             readNum =  new Scanner(new FileInputStream("input.txt"));



             readNum.nextLine();



             //fill Grades array

             for (int i = 0; i < grade.length && readNum.hasNextLine(); i++) 

             {              

                   for (int j = 0; j < grade.length && readNum.hasNextLine(); j++) 

                   {    

                           tempGrade[i][j] = readNum.nextLine();    



                           String tempNum = tempGrade[i][j].replaceAll("[^0-9.0 +$]","");



                            // get the lines



                            String lines = tempNum.split("\r?\n");



                            // get the max amt of nums in a single line



                            for (String x : lines)                        

                            {

                                String temp = x.split("\s+"); 



                                // split on whitespace

                                if (temp.length > maxInLine) 

                                {

                                    maxInLine = temp.length;    



                                }

                            }



                            String array = new String[lines.length][maxInLine]; // declare and instantiate the array of arrays



                            for (int o = 0; o < lines.length; o++) 

                               {    

                                // split on whitespace

                                   String temp = lines[o].split("\s+"); 



                                        for (int f = 1; f < maxInLine; f++) 

                                        {

                                            array[o][f] = (temp[f]);



                                            grade[o][f] = Double.parseDouble(array[o][f]);





                                        }                   

                               }    



                       }    



                }



            readNum.close();

            scan.close();

            writer.close();



        }



        catch(FileNotFoundException e)

        {

            System.out.println("File Not Found");



        }



        return grade;  

}





public static void main(String args) throws IOException, ParseException 

{



    PrintWriter writer = new PrintWriter(new FileOutputStream("Output.txt"));



    String names = null;

    double grades = null;   

    double grade = null;

    double min =null;

    double max =null;

    double average =0;



    grades = processGrades(grade);



    for(int i=0; i < grades.length; i++)

    {

        for(int j=0; j < grades[i].length; j++)

        {

            System.out.println(grades[i][j]);

        }

    }



    writer.close();

}

As you can see, only the last set of grades is printed, the rest displayed as 0.
Output:

16.0

3.0

4.0

2.0

4.0

4.0

7.0

5.0

2.0

3.0

8.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

Please forgive me if the format of the post is hard to read or not right. This is my first time posting question, not sure what need to be done. Thanks

I have to hard code the size for double array, and it works. This is my updated solution.

public static void main(String arg) throws IOException {

    double grades = null;

    double gradelist = Grade(grades);



    for(int i=0; i < gradelist.length; i++) {

        for(int j=0; j < gradelist[i].length; j++) {

            System.out.println(gradelist[i][j]);

        }

    }

}



public static doubleGrade(doublegrade) {

    Scanner in  = null;

    try {

        in = new Scanner(new FileInputStream("input.txt"));         

        in.nextLine();



          int rows = 6;

          int columns = 12;



          grade = new double[rows][columns];



          while(in.hasNextLine())  {

             for (int i=0; i< grade.length; i++) {

                String line = in.nextLine().trim().split(" ");

                for (int j = 1; j < line.length; j++) {

                   grade[i][j] = Double.parseDouble((line[j]));

                }

             }

          }

    }

    catch(Exception e) {

    }



    return grade;

}

I suggest you consider the following approach. It strays quite a bit from your current code but, in my opinion, is much cleaner:

1) Create a class that constructs a student

public class Student {

private String name;

private List<Double> grades; // can be a list of int depending on what you need



public Student(String name) {

    this.name = name;

    grades = new ArrayList<Double>();

}



public void setGrade(Double grade) {

    grades.add(grade);

}





@Override

private String toString() {

    //Override what is automatically printed when you call Student.toString() to print

}

}

Here we have created a student abstraction.

2) A different file reading approach:

public static List<Student> load(String file) throws IOException {

    List<Student> students = new ArrayList<Student>();

    List<String> lines = Files.readAllLines(Paths.get(file));

    for (String line : lines) {

        if (!line.isEmpty()) {

            ArrayList<String> partsOfLine = splitOnSpace(line);

            Student s = new Student(partsOfLine.get(0));

            /* Here, if the number of grades is consistently n, simply use

               s.setGrade(partsOfLine.get(1));

               .

               . 

               s.setGrade(partsOfLine.get(n));

            if not, use some sort of looping to set all grades */

            students.add(s)

        }

    }

return students; // This arrayList can be passed to your print method

}



 public static ArrayList<String> splitOnSpace(String line){

        String splits = line.split(" ");

        return new ArrayList<>(Arrays.asList(splits));

}

3) Sample print method in main

public void print(List<Students> students){

for (Student s: students) {

    System.out.println(s.toString());

}

}