Question

Using Java programming language

Your assignment is to implement a recursive reverse sorting algorithm. It should meet the following requirements:

1. The program shall graphically prompt the user for a file.

2. The program shall read the selected file which will contain 1 integer per line.

3. The program shall sort the values it reads from the file from largest to smallest.

4. The program shall write the values to an output file from largest to smallest in the same directory as the input file.

5. The program shall write 1 integer per line in the output file. 6. The program shall use a recursive algorithm to sort the values.

Answer 1

PLEASE GIVE THUMBS UP, THANKS

SAMPLE OUTPUT :

code:

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Scanner;
import javax.swing.JOptionPane;

/**
*
* @author VISHAL
*/
public class RecursiveSort {
// 1. A recursive function to implement bubble sort sorting algorith
static void bubbleSort(int arr[], int n)
{
// Base case
if (n == 1)
return;
  
// One pass of bubble sort. After
// this pass, the largest element
// is moved (or bubbled) to end.
for (int i=0; i<n-1; i++)
if (arr[i] < arr[i+1])
{
// swap arr[i], arr[i+1]
int temp = arr[i];
arr[i] = arr[i+1];
arr[i+1] = temp;
}
  
// Largest element is fixed,
// recur for remaining array
bubbleSort(arr, n-1);
}
public static void main(String[]args) throws IOException
{
String filename;
String outfilename;
Scanner sc;
FileWriter wr;
ArrayList<Integer> A=new ArrayList<Integer>();
//2. Reading filename Using GUI
filename=JOptionPane.showInputDialog("Enter Input File Name : ");
outfilename=JOptionPane.showInputDialog("Enter OUTPUT File Name : ");
try {
sc=new Scanner(new File(filename));
wr=new FileWriter(outfilename);
} catch (FileNotFoundException ex) {
System.out.println("FILE NOT FOUND, PLEASE CHECK IT");
return;
}
//reading numbers from file
while(sc.hasNextLine())
{
A.add(Integer.parseInt(sc.nextLine()));
}
int []Array=new int[A.size()];
int n=A.size();
for(int i=0; i<A.size(); i++)
{
Array[i]=A.get(i);
}
//doing sorting
bubbleSort(Array,n);
//writing to file
for(int i=0; i<n; i++)
{
wr.write(Array[i]+"\n");
}
wr.close();
sc.close();
System.out.println("Number are written to OUTPUT FILE : "+ outfilename);
}
}