Question

Write a Java class called Grades in a class file called Grades.java.

2. Grades reads from a text file containing a series of course grades (a value between 0.0 and 100.0) with one grade entry per line. However, the first line in the file is an integer value specifying how many grade entries are contained in the file.

3. The Grades class contains four static methods: a. A method called loadGrades() that opens the file, reads in the data and returns an array of double containing grade values. The method takes a single argument called filename of type String that is the name of the file to be opened. If done correctly, the returned array should be the correct size to store all temperature values without any “extra” space within the array. If the file does not exist, then a FileNotFoundException is thrown.

Answer 1

CODE

import java.io.BufferedReader;

import java.io.FileNotFoundException;

import java.io.FileReader;

import java.io.IOException;

public class Grades {

public static double[] loadGrades(String fileName) throws FileNotFoundException {

double[] grades;

try (FileReader reader = new FileReader(fileName);

BufferedReader br = new BufferedReader(reader)) {

int n = Integer.parseInt(br.readLine());

grades = new double[n];

String line;

int i=0;

while ((line = br.readLine()) != null) {

grades[i ++] = Double.parseDouble(line);

}

} catch (IOException e) {

System.err.format("IOException: %s%n", e);

throw new FileNotFoundException();

}

return grades;

}

}