Question

Write a java program to create a student file which includes first name, last name, and GPA. Write another Java program to open the students file. Display the students list and calculate the average GPA of the class.  

Answer 1

Java Program:

(1) File: createStudentFile.java

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

class createStudentFile
{
   //Main method
   public static void main(String[] args) throws FileNotFoundException
   {
       String fName, lName;
       double GPA;
       String loop = "yes";
      
       //Scanner class object
       Scanner reader = new Scanner(System.in);
      
       //PrintWriter object
       PrintWriter writer = new PrintWriter(new File("studentGPA.txt"));
      
       //Reading from user
       while(loop.equalsIgnoreCase("yes"))
       {
           System.out.print("Enter First Name: ");
           fName = reader.nextLine();
           System.out.print("Enter Last Name: ");
           lName = reader.nextLine();
           System.out.print("Enter GPA: ");
           GPA = reader.nextDouble();
          
           //Storing in file
           writer.println(fName + " " + lName + " " + GPA);
           reader.nextLine();
          
           //Prompting user
           System.out.print("\n Do you want add more? (yes/no): ");
           loop = reader.nextLine();
       }
      
       //Closing files
       writer.close();
       reader.close();
   }
}

Sample Run:

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(2) File: CalculateStudentGPA.java

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

class CalculateStudentGPA
{
   //Main method
   public static void main(String[] args) throws FileNotFoundException
   {
       //Scanner object
       Scanner reader = new Scanner(new File("studentGPA.txt"));
      
       String fName, lName;
       double GPA;
       int cnt=0;
      
       double sGPA = 0, aGPA;
      
       //Reading data from file
       while(reader.hasNext())
       {
           fName = reader.next();
           lName = reader.next();
           GPA = reader.nextDouble();
          
           //Printing values
           System.out.println("\n First Name: " + fName + ", Last Name: " + lName + ", GPA: " + GPA);
          
           //Accumulating GPA
           sGPA += GPA;
           cnt++;
       }
      
       //Finding average GPA
       aGPA = sGPA / (double)(cnt);
      
       //Printing average GPA
       System.out.printf("\n\n Average GPA of class: %.2f \n", aGPA);
   }
}

Sample Run: