Question

In java

Q2. Write a program that reads grades of type double of eight students that the user provides. The grades lie between 0 and 10. These grades should be written to a binary file and read from it. The program outputs the highest and lowest grades achieved by students on the screen. The file contains nothing but numbers of type double written to the file with writeDouble.

Answer 1

JAVA Program:

import java.io.DataOutputStream;
import java.io.FileOutputStream;
import java.io.DataInputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.Scanner;

public class WriteDoubleToFile {

public static void main(String[] args) {

String strFilePath = "E://WriteDouble.txt";
  
   double []grades = new double[8];
   double []gradesReadFromFile = new double[8];
  
   int i;
  
   Scanner sc = new Scanner(System.in);
  
   for(i=0;i<8;i++){
       System.out.print("Enter the grade between 0 and 10 for student "+(i+1)+": ");
       grades[i] = sc.nextDouble();
   }
  
   try
{
       FileOutputStream fos = new FileOutputStream(strFilePath);

       DataOutputStream dos = new DataOutputStream(fos);
  
       for(i=0;i<8;i++)
dos.writeDouble(grades[i]);
       dos.close();
      
       FileInputStream fin = new FileInputStream(strFilePath);
      
       DataInputStream din = new DataInputStream(fin);
      
       for(i=0;i<8;i++)
       gradesReadFromFile[i]=din.readDouble();
       din.close();
  
}
catch (IOException e)
{
System.out.println("IOException : " + e);
}
  
   double highest = gradesReadFromFile[0];
   double lowest = gradesReadFromFile[0];
  
   for(i=1;i<8;i++){
       if(gradesReadFromFile[i]>highest)
       highest=gradesReadFromFile[i];
       if(gradesReadFromFile[i]<lowest)
       lowest=gradesReadFromFile[i];
   }
   System.out.println("Highest grade: "+highest);
   System.out.println("Lowest grade: "+lowest);
}
}

Output: