Thread: Nested For...each Loop?

Hi, I have 3 classes in My Program. One is the Main class, another class for students and another class for the subjects and their marks, which are store in arrayLists....

When the student enters his marks an instance of student is created. Now, the student can add more than one subject, thus making student have more than one instance of subject. I need to add the ArrayLists of homeworkMarks in more than one instance subject so that I can work out the average of the 2 subjects together.

Any Idea howe this can be done?

Below is my code... I was thinking of using a nested For each loop, but I'm not 100% sure how to use it :-(

public double homeworkAverage() {
      double homeworkAddition = 0;
 
      for (Subject s : <no idea what to put here>) {
          homeworkAddition = homeworkAddition + homeworkMark.get(i);
      }

Regards

At this point I have one instance of "student".. If the student adds more than one subject, I need to add the homeworkMark of both instances of "student"... Lets say I have

A student who decides to add marks for 2 subjects... thus I have 2 different arrayLists in 2 different instances of subject which I need to add...

You get me?

still cannot get it... this is my full class...

import java.util.ArrayList;
public class Subject
{
   int subjectNumber;
   ArrayList<Double> homeworkMark;
   ArrayList<Double> examinationMark;
   public Subject(int subjectNumber) {
      this.subjectNumber = subjectNumber;  
      this.homeworkMark  = new ArrayList<Double>();
      this.examinationMark = new ArrayList<Double>();
   }
 
   public int getSubjectNumber() {
       return subjectNumber; 
    }
 
   void setSubjectNumber (int subNum) {
        subjectNumber= subNum;
   }
 
 
   public double homeworkAverage() {
      double homeworkAddition = 0;
        for(double s : homeworkMark) {
              homeworkAddition = homeworkAddition + s;   
            }
      //works out the average of the homewrok marks entered
      double homeworkAverage = homeworkAddition/homeworkMark.size();
      return homeworkAverage;
    }
 
   public double examinationAverage() {
      //Works out the addition of the arrayList examinationMark
      double examinationAddition = 0;
      for (int i = 0; i <= examinationMark.size()-1; i++) {
          examinationAddition = examinationAddition + examinationMark.get(i);
      }
      //works out the average of the homework marks entered
      double examinationAverage = examinationAddition/examinationMark.size();
 
      return examinationAverage;
   }
 
   public double overallMark() {
       double overallMark = ((20.0/100.0) * homeworkAverage()) + ((80.0/100.0) * examinationAverage());
       return overallMark;
   }
 
   public char gradeChecker(){
       char grade ='F';
              if(overallMark() >= 75) {
                grade = 'A'; 
              }
              else if (overallMark() >= 60 && overallMark() < 75){
                grade = 'B'; 
              }
              else if (overallMark() >= 50 &&  overallMark() <= 60){
                grade = 'C'; 
              }
              else if (overallMark() >= 40 &&  overallMark() <= 50){
                grade = 'D'; 
              }
              else if (overallMark() >= 35 &&  overallMark() <= 40){
                grade = 'E'; 
              }
              else if (overallMark() < 35 ){
                grade = 'F'; 
              }
 
        return grade;
   }
 
   public void addToHomeworkMark(double homeMark) {
       homeworkMark.add(homeMark);
   }
 
   public void addToExaminationMark(double examMark) {
       examinationMark.add(examMark);
   }
}

I need this to work for both homeworkMark and examinationMark. Att the moment its only calculating of the last subject entered and not of the first and the second together.

I'm totally lost :/

regards, and thanks in advance

The user must... enter name, surname student number.... thats one class...

then it asks him to enter marks for hw and exams for one subject, so thats an instance of subject...in array sub...

it asks if he wants to enter again, if yes, a new instance of subject is created and put into array sub, again with the arraylist of hw marks and exam marks...

I must add arraylist of HomeworkMark of the first subject he added, with the arraylist of homework marks of the second subject he entered. These are both in arraylist sub... in the main method...

Mind-f*ck in my op

I need that it works out the addition of both arrayLists of the subject together. SO i can work out an overall average.

Example: I'm malcolm, and I have 2 subjects... English and Maltese. I need to add the marks of both of them(both instances of subject) so that ill be able to work an average.

Originally Posted by KevinWorkman

We're going in circles now, but the question remains: what about those requirements are you stuck on?

Yes we are, haha.

Ok, so basically...If The user enters the the marks for the first subject.... (example: 20, 30 and 40)
The enters the marks for the second subject ( example 50, 60 and 70);

The program works out the addition of subject 1 alone (20 + 30 + 40) and of subject 2 alone (50 + 60 + 70)

I require to add both arrayLists of the subjects in both instances of subject to get the addtion of ( 20 +30 + 40 +50 +60 +70)

Thats where I am stuck. How can i access both homeworkMark arrayLists from my 2 different instances of subject?? If you require me to send you the file, I'll send it as a link in a private message.