Problem calculating a score

[marco01]

Hi Everyone,

Days that I'm on that problem. I have to calculate a substitution score.

Below my code:

public void calcSubstitutionScore()   
   {
      substitutionScore = (average + examMark) /2; 
   }

I previously created the method average, and I try to add to it examMark divide by two, which is suppose to give the substitutionscore. I get a syntax error:

operator + cannot be applied to java.util.List<Java.lang.Integer>,int

I have problem how to deal with Integer:'(

[javaAddict]

One of your variables is a List, so natuarally you cannot add ("+") a list to an integer

[marco01]

One of your variables is a List, so natuarally you cannot add ("+") a list to an integer

Thanks JavaAddict for your reply:)

I change my code to go around that problem, I get no syntax error but instead I get a semantic error:(

public void calcSubstitutionScore()   
   {
      List<Integer> subScore = new ArrayList<Integer>();
      int size = tmaMarks.size();
      List<Integer> average = new ArrayList<Integer>();
      getTmaMarks();
      getExamMark();
      int tmaMarks = (size/4);
      substitutionScore = (subScore.get(tmaMarks) + subScore.get(examMark))/2; 
   }

Here is the semantic error:

Exception: java.lang.IndexOutOfBoundsException: Index: 1, Size: 0

:?:

[javaAddict]

Again you cannot access the elements of a list without checking their size. When you are calling this:
subScore.get()
you need to make sure that the argument is between 0 and size()
According to the error your list is empty

[marco01]

Again you cannot access the elements of a list without checking their size. When you are calling this:
subScore.get()
you need to make sure that the argument is between 0 and size()
According to the error your list is empty

I just show below how I'm suppose to test the method calcSubstitutionScore() in the displaypanel:

Student n = new Student("Becca");// line 1
Integer[] numberArray = {5, 6, 7, 8};// line 2
n.setTmaMarks(Arrays.asList(numberArray));// line 3
n.setExamMark(61);// line 4
n.calcSubstitutionScore();// line 5

I'm lost, I don't see how to check the size of the list, I thought line 2 3 and 4 gave check the size.

[javaAddict]

In your calcSubstitutionScore method you create new lists. You don't use the ones with the scores

[marco01]

In your calcSubstitutionScore method you create new lists. You don't use the ones with the scores

I'm still working on that problem. I can't figure it out, would it be possible to give me a similar example, or even would you know where can I look for a tutorial on the subject.:)

[javaAddict]

post the Student class

[javaAddict]

I'm still working on that problem. I can't figure it out, would it be possible to give me a similar example, or even would you know where can I look for a tutorial on the subject.:)

Well I will repeat myself. In the calcSubstitutionScore you create new List: List<Integer> subScore = new ArrayList<Integer>() that has no elements inside. And then you are trying to access it, so naturally this: subScore.get(tmaMarks) will not work since it has no elements.
Shouldn't you be using the private subScore List after you enter some values to it, instead of creating a new one with no values?

Secondly, did the average method had an argument or you added it. Because I believe that it should calculate the average value of one the lists declared in the class, but again I don't know what it is supposed to do.

[marco01]

Thanks javaAddict for your help, I finally got it:) :icon_idea: