Question

How can I make this program sort strings that are in a text file and not have the user type them in? I need this done by 5:00 AM EST tommorow please.

import java.util.*;
public class MergeDemo
{
public static void main(String args[])
{
Scanner input=new Scanner(System.in);
System.out.print("How many lines to be sorted:");
int size=input.nextInt();
String[] lines=new String[size];
lines[0]=input.nextLine();
System.out.println("please enter lines...");
for(int i=0;i {
lines[i]=input.nextLine();
}
System.out.println();
System.out.println("Lines Before Sorting:");
System.out.println(Arrays.toString(lines));
mergeSort(lines);
System.out.println();
System.out.println("Lines after Sorting:");
System.out.println(Arrays.toString(lines));
}

public static void mergeSort(String[] s)
{
if(s.length>1)
{
String[] left=Arrays.copyOfRange(s,0,s.length/2);
String[] right=Arrays.copyOfRange(s,s.length/2,s.length);
mergeSort(left);
mergeSort(right);
merge(s,left,right);
}
}
public static void merge(String[] result, String[] left, String[] right)
{
int i1 = 0;
int i2 = 0;
for (int i = 0; i < result.length; i++)
   {
   if (i2 >= right.length || (i1 < left.length &&left[i1].compareToIgnoreCase(right[i2])<0))
   {
result[i] = left[i1];
i1++;
}
   else
   {
result[i] = right[i2];
i2++;
}
}
}
}

Answer 1

Code:

First, save the below strings in a text file.

Input.txt

56
Rick
Daryl
Abhi
81
Jeet
Alex
Max
Carol
Vikas
Boss
Nitesh
62

Java Code:

StringSorting.java

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;

public class StringSorting
{   
public static void main(String[] args)
{   
BufferedReader reader = null;

BufferedWriter writer = null;

//Create an ArrayList object to hold the lines of an input file

ArrayList<String> lines = new ArrayList<String>();

try
{
//Creating BufferedReader object to read the input file

reader = new BufferedReader(new FileReader("input.txt"));

//Reading all the lines of input file one by one and adding them into ArrayList

String currentLine = reader.readLine();

while (currentLine != null)
{
lines.add(currentLine);

currentLine = reader.readLine();
}

//Sorting the ArrayList

Collections.sort(lines);

//Creating BufferedWriter object to write into the output file

writer = new BufferedWriter(new FileWriter("output.txt"));

//Writing sorted lines into output file

for (String line : lines)
{
writer.write(line);

writer.newLine();
}
}
catch (IOException e)
{
e.printStackTrace();
}
finally
{
//Closing the resources

try
{
if (reader != null)
{
reader.close();
}

if(writer != null)
{
writer.close();
}
}
catch (IOException e)
{
e.printStackTrace();
}
}
}   
}

Output Text File will be generated like below sorted strings.

Output.txt:

56
62
81
Abhi
Alex
Bhavani
Carol
Daryl
Jeet
Max
Nalini
Rick
Vikas

Screenshots:

Input Text file ScreenShot:

Output Text file Screenshot:

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