Some help with Java....

• ndmmxiaomayi

  13 Jul 06, 12:40

  How to calculate mean?
  
  I'm given a CSV file, and supposed to use this file to calculate the mean.
  
  Using Apache Math Commons Package to calculate the mean.
  
  rawscores.csv file
  
  I write until here then stuck liao. Click on Edit to see the whole code... if not, some become emoticons...
  
  

  code:

  import java.io.*;
  import opencsv.*;
  import org.apache.commons.math.*;
  
  public class Main {
  
  Main() {
  grades = new StudentGrade[202];
  }
  StudentGrade[] grades;
  
  void readScores() throws IOException {
  String RAWSCORES="rawscores.csv";
  
  CSVReader reader = new CSVReader(new FileReader(RAWSCORES));
  String [] nextLine = reader.readNext(); // read the 1st line
  
  while (nextLine != null) {
  //
  // there are 2 columns in the CSV, we access each column using the array index
  //
  System.out.println("Name: [" + nextLine[0] + "]");
  System.out.println("Score: [" + nextLine[1] + "]");
  
  nextLine = reader.readNext(); // read the following line
  }
  
  }
  
  double calcMean() {
  return 0;
  }

• MosPosterior

  13 Jul 06, 12:57

  ok... here is a sample class I had done...
  
  

  code:

  class test{
  public static void main(String argu[]){
  int StudentGrade[] = {1,2,3,4,5};
  double mean = 0, total = 0;
  for (int i=0;itotal += StudentGrade[i];
  }
  mean = total/StudentGrade.length;
  System.out.print(mean +"\n");
  }
  }

  
  
  

  code:

  Most importantly is this part only..
  double mean = 0, total = 0;
  for (int i=0;itotal += StudentGrade[i];
  }
  mean = total/StudentGrade.length;

• ndmmxiaomayi

  13 Jul 06, 13:34

  
  
  Everything kosong....
• MosPosterior

  13 Jul 06, 13:41

  code:

  Main() {
  grades = new StudentGrade[202];
  }
  StudentGrade[] grades;

  
  
  haha.. because of this line...
  
  The StudentGrade is another class... for example, it should be StudentGrade[i].grade()
  
  You need to parse the variables from that StudentGrade class here, either by extend or same package..
  
  Haha... show me all your .java files? I help you write..
• ndmmxiaomayi

  13 Jul 06, 13:58

  Originally posted by MosPosterior:
  [b]

  code:

  Main() {
  grades = new StudentGrade[202];
  }
  StudentGrade[] grades;

  
  
  haha.. because of this line...
  
  The StudentGrade is another class... for example, it should be StudentGrade[i].grade()
  
  You need to parse the variables from that StudentGrade class here, either by extend or same package..
  
  Haha... show me all your .java files? I help you write.. [/b]

  I don't have so dumb to copy and paste everything...
  
  Main.java
  
  StudentGrade.java
  
  Haha, happy solving, I already confuse liao.
• MosPosterior

  13 Jul 06, 14:31

  Done ^__^
  
  

  code:

  import java.io.*;
  import opencsv.*;
  import org.apache.commons.math.*; //redundant - can be deleted
  
  public class Main {
  static String RAWSCORES ="rawscores.csv";
  public static void main(String argu[]){ //Main is deleted, redundant also
  try{
  readScores();
  System.out.print("\n\n" +calcMean() +"\n");
  }catch(IOException e){
  System.err.println(RAWSCORES +" not found");
  }
  }
  
  static void readScores() throws IOException {
  CSVReader reader = new CSVReader(new FileReader(RAWSCORES));
  String [] nextLine = reader.readNext();
  while (nextLine != null) {
  System.out.println("Name: [" + nextLine[0] + "]");
  System.out.println("Score: [" + nextLine[1] + "]");
  
  nextLine = reader.readNext();
  }
  }
  
  static double calcMean() throws IOException{
  CSVReader reader = new CSVReader(new FileReader(RAWSCORES));
  String [] nextLine = reader.readNext();
  double total = 0;
  while (nextLine != null) {
  total += Double.parseDouble(String.valueOf(nextLine[1]));
  nextLine = reader.readNext(); //normal mean cal. here
  }
  return Math.round(total/202); //optional
  }
  }

• stellazio

  13 Jul 06, 14:57

  
• lpx88

  13 Jul 06, 20:12

  wah we hav java pros ere lol
• ndmmxiaomayi

  13 Jul 06, 22:55

  Originally posted by stellazio:

  

  Why this face? I don't know, ask here lor. Teacher not in class ma.