Combining all classes under a single class/program

Question

Below is the java code I have written to read the information and print the following information by creating various classes and methods.

Name:…… (name of student)
Current GPA:…..
Current grade average:…..

Can this be reduced to a single program/class by combining all the classes under a single program i.e without creating different classes?

Student class:

public class Student
{
   private String name;
   private double gpa;

   //methods
   public Student(){}


   public Student(String n,double g)
   {
   name=n;
   gpa=g;
   }
   //set the first name
   public void setName(String n)
   {
    name=n;
   }
    public void setGpa(double g)
   {
    gpa=g;
   }   
   //get methods
   public String getName(){return name;}
   public double getGpa(){return gpa;}
}

Marks class:

public class Marks extends Student
{
   //data
   private int grade[];

   //methods

   public Marks()
   {
   super();
   grade=new int[0];
   }

   public Marks(String n,double g, int k[])
   {
   super(n,g);
   grade=new int[k.length];
   for(int i=0;i<k.length;i++)
      grade[i]=k[i];
   }

   //average method
   public double  average()
   {
   double sum=0;
   for(int i=0;i<grade.length;i++)
   sum+=grade[i];
   return sum/grade.length;
   }  
}

Main class:

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

public class Lab
{
   public static void main(String args[]) throws Exception
   {
   //data
   Student list[];  
   String name;
   double gpa;
   int k[], i,j;
   File toRead= new File("input.txt");
   Scanner get=new Scanner(toRead);

   //read input
   list=new Student[get.nextInt()];
   for(i=0;i<list.length;i++)
      {
          get.nextLine();
          name=get.nextLine();
          gpa=get.nextDouble();
          int gn=get.nextInt();
          k=new int[gn];
          for(j=0;j<k.length;j++)
          k[j]=get.nextInt();

          list[i]=new Marks(name,gpa,k); 
      }


   //print all the  name
   for(i=0;i<list.length;i++)
      System.out.printf("Name:%s\nGpa:%.2f\n",list[i].getName(),list[i].getGpa());


   //print average grades for student
   for(i=0;i<list.length;i++)
       {
       if(list[i] instanceof Marks)
         {
         Marks s=(Marks)list[i];
         System.out.printf("average: %s- %.2f\n", s.getName(),s.average());
         }
       }
   }
}

input.txt

3
Mark antony
3.4
10
100 100 90 80 34 56 78 90 89 80
Alex Smith Jr.
2.9
5
100 95 98 78 80
Mary J. John
3.4
12
35 56 100 100 90 98 87 89 88 77 67 95

Do you mean you'd like to put all the classes in one source file, or _really_ get rid of all the classes and use only one class? The first can be done, the second makes no sense at all. Please clarify. — Jim Garrison, Feb 12 '17 at 06:39
It can. But I think the question is... should you do this? And the answer is no. — Luke Joshua Park, Feb 12 '17 at 06:39
You might want to simply [package all the classes into an executable jar](http://stackoverflow.com/questions/5258159/how-to-make-an-executable-jar-file). — Andrew Jenkins, Feb 12 '17 at 06:40
We are asked to write the code without creating multiple classes like I did. — Apple, Feb 12 '17 at 06:50
can a singe code be written for the above input file to produce the below output: — Apple, Feb 12 '17 at 06:53
OUTPUT: Name:Mark antony Gpa:3.40 Name:Alex Smith Jr. Gpa:2.90 Name:Mary J. John Gpa:3.40 average: Mark antony- 79.70 average: Alex Smith Jr.- 90.20 average: Mary J. John- 81.83 — Apple, Feb 12 '17 at 06:54

score 0 · Answer 1 · answered Feb 12 '17 at 06:43

You can do nesting of classes. But better way can be Declare a single class as Student and write a functions with respect to Marks which performs the calculations. Method call is always possible from class. This will minimize the code.

Combining all classes under a single class/program

1 Answers1