Calling an array that's inside another array

Question

Bear with me, this is a bit long. This class here is creating a student object:

public class Student {
    String firstName;
    String lastName;
    int assignmentScores[];
    int labScores[];
    int attendanceScore;
    int totalHomeworkScore;
    int midterm1;
    int midterm2;
    int finalExam;
    int zyanteScore;
    int patScore;
    int totalTestScore;
    String letterGrade;

    public Student() {

    }

    public void setFirstName(String fName) {
        firstName = fName;

    }

    public String getFirstName() {
        return firstName;
    }

    public void setLastName(String lName) {

        lastName = lName;
    }

    public String getLastName() {
        return lastName;
    }

    public void setAssignmentScores(int[] assignmentScore) {
        assignmentScores = assignmentScore;
    }

    public int[] getAssignmentScores() {
        return assignmentScores;
    }

    public void setLabScores(int[] labScore) {
        assignmentScores = labScore;
    }

    public int[] getLabScores() {
        return labScores;
    }

    public void setAttendanceScore(int attenScore) {
        attendanceScore = attenScore;
    }

    public int getAttendanceScore() {
        return attendanceScore;
    }

    public void setTotalHomeworkScore(int hScore) {
        totalHomeworkScore = hScore;
    }

    public int getTotalHomeworkScore() {
        return totalHomeworkScore;
    }

    public void setMidTerm1(int mT1) {
        midterm1 = mT1;
    }

    public int getMidterm1() {
        return midterm1;
    }

    public void setMidterm2(int mT2) {
        midterm2 = mT2;
    }

    public int getMidterm2() {
        return midterm2;
    }

    public void setFinalExam(int fExam) {
        finalExam = fExam;
    }

    public int getFinalExam() {
        return finalExam;
    }

    public void setZyanteScore(int zyant) {
        zyanteScore = zyant;
    }

    public int getZyanteScore() {
        return zyanteScore;
    }

    public void setPatScore(int pat) {
        patScore = pat;
    }

    public int getPatScore() {
        return patScore;
    }

    public void setTotalTestScore(int tScore) {
        totalTestScore = tScore;
    }

    public int getTotalTestScore() {
        return totalTestScore;
    }

    public void computeGrade() {
        if (getTotalHomeworkScore() <= 599 || getTotalTestScore() <= 149
                || getTotalHomeworkScore() <= 719 && getTotalTestScore() <= 179
                || getTotalHomeworkScore() <= 779 && getTotalTestScore() <= 164
                || getTotalHomeworkScore() <= 659 && getTotalTestScore() <= 209) {
            letterGrade = "P";
        }

        if (getTotalHomeworkScore() >= 1140 && getTotalTestScore() >= 180
                || getTotalHomeworkScore() >= 1080
                && getTotalTestScore() >= 195 || getTotalHomeworkScore() >= 960
                && getTotalTestScore() >= 210 || getTotalHomeworkScore() >= 900
                && getTotalTestScore() >= 225 || getTotalHomeworkScore() >= 840
                && getTotalTestScore() >= 240 || getTotalHomeworkScore() >= 780
                && getTotalTestScore() >= 255 || getTotalHomeworkScore() >= 720
                && getTotalTestScore() >= 285) {
            letterGrade = "G";
        } else {
            letterGrade = "A";
        }
    }

    public String getGrade() {
        return letterGrade;
    }

}

This class creates a student object, with values to be set from a text file. This next class creates an array of these student objects, as well as a few other things that aren't important at the moment. The important method right now is the setStudents method, which is creates the array of student objects:

 public class CourseOffering {
    Student[] students;
    String description;
    double homeworkAverage;
    double testAverage;
    int passingStudents;

    public CourseOffering() {

    }

    public void setStudents(Student[] studentArray) {
        students = studentArray;
    }

    public void setDescription(String descript) {
        description = descript;

    }

    public String getDescription() {
        return description;
    }

    public double computeHomeworkAverage() {
        int temp = 0;
        for (int i = 0; i < students.length; i++) {
            temp += students[i].getTotalHomeworkScore();
        }
        homeworkAverage = temp / students.length;
        return homeworkAverage;
    }

    public double computeTestAverage() {
        int temp = 0;
        for (int j = 0; j < students.length; j++) {
            temp += students[j].getTotalTestScore();
        }

        testAverage = temp / students.length;
        return testAverage;
    }

    public int countPassingStudents() {
        int temp = 0;

        for (int k = 0; k < students.length; k++) {
            if (students[k].getGrade() == "G") {
                temp++;
            }
        }
        passingStudents = temp;
        return passingStudents;

    }

}

Finally, this class is the driver that is running the entire thing:

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

public class CourseStatistics {
    static int numberOfClasses = 3;
    static int numberOfStudents = 4;
    static int numberOfAssignments = 7;

    public static void main(String[] args) {
        CourseOffering myCourseOffering = new CourseOffering();
        Student myStudent = new Student();
        myCourseOffering.students = new Student[numberOfStudents];



        Scanner scanner = new Scanner(System.in);
        try {
            scanner = new Scanner(new File("gradesA5.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);
        }

        numberOfClasses = scanner.nextInt();
        System.out.println(numberOfClasses);

        for (int i = 0; i < numberOfClasses; i++) {
            for (int j = 0; j < numberOfStudents; j++) {
                myCourseOffering.students[i] = new Student();

                myCourseOffering.setDescription(scanner.next()); // CSCE
                myCourseOffering.setDescription(scanner.next()); // 155A
                myCourseOffering.setDescription(scanner.next()); // -

                myCourseOffering.setDescription(scanner.next()); // Reads
                                                                    // Semester
                System.out.print(myCourseOffering.getDescription() + " "); // Prints
                                                                            // Semester

                myCourseOffering.setDescription(scanner.next()); // Reads Year
                System.out.println(myCourseOffering.getDescription()); // Prints
                                                                        // Year

                numberOfStudents = scanner.nextInt(); // Number Of Students
                System.out.println(numberOfStudents); // Prints number of
                                                        // students

                System.out.println("Name" + "\t" + "\t" + "Assignment Score"
                        + "\t" + "Test Score" + "\t" + "Grade");

                myCourseOffering.students[j].setFirstName(scanner.next());
                System.out.print(myCourseOffering.students[j].getFirstName()
                        + " ");

                myCourseOffering.students[j].setLastName(scanner.next());
                System.out.print(myCourseOffering.students[j].getLastName());

                for (int k = 0; k < numberOfAssignments; k++) {
                myCourseOffering.students[j].assignmentScores[k].setAssignmentScores(scanner.nextInt());
            }
            }
        }

    }
}

What I can't figure out is how to call an array that is inside the student objects array in courseOfferign. I want to call these two methods:

public void setAssignmentScores(int[] assignmentScore) {
        assignmentScores = assignmentScore;
    }

    public int[] getAssignmentScores() {
        return assignmentScores;
    }

which are both part of the student object array in CourseOffering. I tried to do something similar to when I got the first and last name from the student object array, which I did in this for loop :

for (int k = 0; k < numberOfAssignments; k++) {
                    myCourseOffering.students[j].assignmentScores[k].setAssignmentScores(scanner.nextInt());
            }

But obviously that doesn't work. I'm trying to fill the assignmentScore array with the line of numbers in the text file. I assume I have to somehow initialize a new array, but I'm not sure how and where to do it. This is the text file I am attempting to read:

3
CSCE 155A - Fall 2011
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
CSCE 155A - Spring 2012
1
Paul Kubi     80    90  5   87  80  0   25  0   20  22  21  24  19  22  21  0   24  21  20  25  20  0   0   0   30  20  25  8
CSCE 155A - Fall 2012
3
Tianna Delp   99    99  99  99  99  99  24  15  16  21  25  15  19  20  21  22  21  21  23  15  15  60  50  60  20  17  20  9
Taylor Delp   95    92  80  90  82  78  25  25  25  25  24  10  25  25  25  25  25  25  25  25  25  58  51  95  28  14  28  7
Rachel Valenz 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

can you narrow down your problem.? so that you can get your solution quickly. — Rajaprabhu Aravindasamy
– Rajaprabhu Aravindasamy, Commented Nov 18, 2013 at 18:59
Also it may be better to look into using Collection and its variants for something this large. — Rogue
– Rogue, Commented Nov 18, 2013 at 19:01

Ankit Rustagi · Accepted Answer · 2013-11-18 19:22:12Z

2

Your method setAssignmentScores expects an int array as a parameter, you are sending in one single integer, which is incorrect.

myCourseOffering.students[j].assignmentScores[k].setAssignmentScores(scanner.nextInt());

Instead, build an array and pass it

int[] myArray = new int[numberOfAssignments];    // notice this
for (int k = 0; k < numberOfAssignments; k++) {
  myArray[i] = scanner.nextInt();
}
myCourseOffering.students[j].assignmentScores[k].setAssignmentScores(myArray);

edited Nov 18, 2013 at 19:22

answered Nov 18, 2013 at 18:59

Ankit Rustagi

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6 Comments

user2120893 Over a year ago

So what you're saying is to read individual integers and then store it in a new array, and then pass that to the array that I was trying to call?

Ankit Rustagi Over a year ago

Yes, pass the array to setAssignmentScores function.

user2120893 Over a year ago

Ok, so I tried that, but I got the error message "Cannot invoke setAssignmentScores(int[]) on the primitive type int".

Ankit Rustagi Over a year ago

Sorry, we need to use int[] and not Integer[], i have made the change please see my edit

Ankit Rustagi Over a year ago

This is because the function expects int[]

|

Jack · Accepted Answer · 2013-11-18 19:03:57Z

If you don't want to expose directly the array then you can choose between two equal ways:

1) build the array and then set it

int[] tempAssignments = new int[numberOfAssignments];
for (int i = 0; i < numberOfAssignments; ++i)
  tempAssignments[i] = scanner.nextInt();
student.setAssignmentScores(tempAssignments);

2) initialize the array in Student and fill it with data

class Student {
  void initializeAssignments(int count) {
    assignmentScores = new int[count];
  }
  void setAssignmentScore(int index, int value) {
    assignmentScores[index] = value;
  ..
}

student.initializeScores(numberOfAssignments);
for (int i = 0; i < numberOfAssignments; ++i)
  student.setAssignmentScore(i, scanner.nextInt());
}

Or you can just use a List<Integer> and live in peace:

class Student {
  final List<Integer> assignmentScores = new ArrayList<Integer>();

  void addScore(int score) {
    assignmentScore.add(score);
  }
}

for (int i = 0; i < numberOfAssignments; ++i)
  student.addScore(scanner.nextInt());

Sage · Accepted Answer · 2013-11-18 19:07:53Z

1

public void setAssignmentScores(int[] assignmentScore)

You are calling this function with passing an integer instead of an array:

myCourseOffering.students[j].assignmentScores[k].setAssignmentScores(scanner.nextInt());

Try to read the assignment score at once to save in an array and then invoke this function with the array.

int assignScores[] = new int[numberOfAssignments] ;
for (int k = 0; k < numberOfAssignments; k++) {
    assignScores[k] =  scanner.nextInt();
}

 myCourseOffering.students[j].assignmentScores[k].setAssignmentScores(assignScores);

edited Nov 18, 2013 at 19:07

answered Nov 18, 2013 at 19:01

Sage

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Comments

The Guy with The Hat · Accepted Answer · 2013-11-18 23:52:57Z

1

The problem is in the line

myCourseOffering.students[j].assignmentScores[k].setAssignmentScores(scanner.nextInt());

assignmentScores is an array of ints, and setAssignmentScores() is a method of the class Student, not the class int. In .assignmentScores[k].setAssignmentScores(..., you are trying to call int's method .setAssignmentScores(..., which doesn't exist. Instead, you need to call Student's method.

Look at the code below, which should replace the line myCourseOffering.students[j].assignmentScores[k].setAssignmentScores(scanner.nextInt());

int[] scores = new int[numberOfAssignments];
for(int k = 0; scanner.hasNextInt(); k++)
{
    scores[k] = scanner.nextInt();
}
myCourseOffering.students[j].setAssignmentScores(scores);

edited Nov 18, 2013 at 23:52

answered Nov 18, 2013 at 19:10

The Guy with The Hat

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Comments

Big Al · Accepted Answer · 2013-11-18 19:03:49Z

0

Make assignmentScores an ArrayList or Collection.
I would make a method called addAssignmentScore() that adds to the array of assignment scores.

answered Nov 18, 2013 at 19:03

Big Al

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