java - Is it possible to return or somehow access the data from "courses" from this method? -

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i'm working on first programming assignment java , had question. put course[] inside of student[] seem encountering nullpointerexception error , can't figure out why.

public student[] analyzedata() {     scanner inputstream = null;      try {         inputstream = new scanner(new fileinputstream("programming assignment 1 data.txt"));     } catch (filenotfoundexception e) {         system.out.println("file programming assignment 1 data.txt not found or opened.");         system.exit(0);     }      int numberofstudents = inputstream.nextint();     int tuitionperhour = inputstream.nextint();      student[] students = new student[numberofstudents];     (int = 0; < numberofstudents; i++) {         string firstname = inputstream.next();         string lastname = inputstream.next();         int studentid = inputstream.nextint();         string istuitionpaid = inputstream.next();         int numberofcourses = inputstream.nextint();           course[] courses = new course[numberofcourses];         (i = 0; < numberofcourses; i++) {             string coursename = inputstream.next();             string coursenumber = inputstream.next();             int credithours = inputstream.nextint();             string grade = inputstream.next();             course currentcourse = new course(coursename, coursenumber, credithours, grade);             courses[i] = currentcourse;         }         student currentstudent = new student(firstname, lastname, studentid, istuitionpaid, numberofcourses, courses);         students[i] = currentstudent;     }     return students; }

the formatting input file is:

3 345 lisa miller 890238 y 2  mathematics mth345 4 physics phy357 3 b   bill wilton 798324 n 2 english eng378 3 b philosophy phl534 3

where courses has information courses, , students has information students.

i add array (or better yet, arraylist or map) student contains classes student taking.

with you're doing, how determining classes go students?

try adding following instance variable

  private list<course> courses;

to student, implement following methods add list or return whole thing.

  void addcourse(course c) { /*code here*/ };   list getcourses() {/* code here */} ;

and reading files can real pain, have ok, @ least now. loop course instantiated include call student.addcourse(course). you'll golden.

be advised high level overview there learnage in here you. post , we'll help.


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