Java Data Structures and Big-Oh Performance Estimation Create a class for testin

Question

Java Data Structures and Big-Oh Performance Estimation

Create a class for testing data structures. This class should be able to read and write text files. It should be able to store this in index integer fields.

This class needs 5 index integer fields (first name, last name, year, gpa, major). Use String, int, and double types.

Write a method that will create an array of N random instances of this class where N is an integer parameter to this method. Use this for gpa random between 2.0 and 4.0.

Provide a toString method that will format an instance of this class nicely.

Provide appropriate constructors.

Write methods that will write and read text files of this class:

o to make this easy, assume that the first line of the file is the number of elements in the file
o make the file one line per entry
o use spaces as field delimiters in the files
o use the toString method of the class to write to the file

text files to be read can look like this:

Bobby Ong 1 3.9 ComputerScience
Martha Jones 2 3.5 English
Jane Sully 3 3.2 Nursing
Thomas Berkley 4 3.6 Business
Michael Smith 5 3.0 ComputerScience

Provide a good GUI interface to control and test this class:

o use buttons to control the functions available
o use JFileChoose for selecting input and output files
o use a JTextArea and JScrollPane to create a scrolling text area for output
o the window should resize nicely - use BorderLayout with the text area in the center

Explanation / Answer

import java.io.*;
import java.util.*;

class performance{
   String first_name;
   String last_name;
   int year;
   double gpa;
   String major;
   public performance(String f,String l,int y,double cg,String m){
       first_name = f;
       last_name = l;
       year       = y;
       gpa        = cg;
       major      = m;
   }
   public String toString(){
       return "first name : "+first_name+" last name : "+last_name+" year : "+year+" gpa : "+gpa+" major : "+major+" ";
   }
}

class main{
   public static void random_ins(int n){
       performance[] per = new performance[n];
       Scanner sc = new Scanner(System.in);
       for (int i = 0; i < n; i++){
           System.out.print("Enter first name : ");
           String first_name = sc.next();
           System.out.print("Enter last name : ");
           String last_name = sc.next();
           System.out.print("Enter year of entrance : ");
           int year = sc.nextInt();
           System.out.print("Enter your CGPA : ");
           double gpa = sc.nextDouble();
           System.out.print("Enter your major : ");
           String major = sc.next();
           performance p = new performance(first_name,last_name,year,gpa,major);
           per[i] = p;
       }
   }
   public static void main(String[] args){
       performance[] per = new performance[100];
       int size = 0;
       BufferedReader br = null;
       try{
           String line;
           br = new BufferedReader(new FileReader("input.txt"));
           while ((line = br.readLine()) != null){
               String[] temp = line.split(" ");
               performance p = new performance(temp[0],temp[1],2015,Double.parseDouble(temp[3]),temp[4]);
               per[size] = p;
               size += 1;
           }
       }
       catch (IOException e) {
           e.printStackTrace();
       }
   }
}

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