Programming Exam 1st

// Class StudentLog
import java.util.Scanner;
import java.util.ArrayList;
import java.io.File;
import java.io.PrintWriter;

class StudentLog {

  public static void printStudent(String n, int id)
  {
   System.out.println(id+ " " + n);
  }

  public static StudentInfo[] sortedList(ArrayList<StudentInfo> a)
  {
   StudentInfo[] ob = new StudentInfo[a.size()];
    for (int q = 0 ; q < a.size() ; q++)
    {
     ob[q] = a.get(q);
    }
    // sorted
   for (int q = 0 ; q < ob.length ; q++)
   {
    for (int w = q ; w < ob.length ; w++)
    {
     if (ob[q].id < ob[w].id)
     {
      StudentInfo f = ob[q];
      ob[q] = ob[w];
      ob[w] = f;
     }
    }
   }
   return ob;
  }



  public static void main (String [] args) throws Exception{
    // Read
    File f = new File("student_log.txt");
    Scanner s = new Scanner(f);
    ArrayList<StudentInfo> as = new ArrayList<StudentInfo>();
    while(s.hasNextLine())
    {
     int id = s.nextInt();
     String name = s.nextLine();
     StudentInfo si = new StudentInfo(name, id);
     as.add(si);
    }
    s.close();
    // Sorted
    StudentInfo [] ob = sortedList(as);
    for (StudentInfo studentInfo: ob)
    {
     printStudent(studentInfo.name, studentInfo.id);
    }
    // Write
    File nf = new File("student_log_sorted.txt");
    PrintWriter pw = new PrintWriter(nf);
    for (StudentInfo studentINFO : ob)
    {
     pw.print(studentINFO.id + " ");
     pw.println(studentINFO.name);
    }
    pw.close();
  }
}

// Class StudentInfo
// Keep ID-name of one member (student)
class StudentInfo {
  public String name;
  public int id;

  public StudentInfo(String n, int id)
  {
   this.name = n;
   this.id = id;
  }
}