import java.io.File;
import java.io.FileNotFoundException;
import java.io.PrintWriter;
import java.util.Scanner;
import java.util.ArrayList;

/**
Removes blank lines from a file
*/
public class DeleteBlankLines
{
   /**
Removes blank lines from the file given as argument and writes the non-blank lines
back to the file.
@param fileName the name of the file to be processed.
*/
public static void removeLines(String fileName)
{
// list to hold the non-blank lines
   ArrayList lines = new ArrayList();
 
//-----------Start below here. To do: approximate lines of code = 8
// In a try {..} block, create a File object using the fileName parameter,
   // then create a Scanner object passing in the File reference
   // then read the lines one by one. Check if the line string is non-blank by making use of the String class trim()
   // method. After trimming, check the size of the string to see if it is > 0 (or use isEmpty() method)
   // If it is > 0, add the line to the lines array list
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
//-----------------End here. Please do not remove this comment. Reminder: no changes outside the todo regions.
 
//-----------Start below here. To do: approximate lines of code = 7
// In a try {..} block, create a file for writing using the PrintWriter class and the same parameter fileName
   // as above. Then output the lines in the array list to this file. Don't forget to close the file!!
 
 
 
 
 
 
 
 
 
 
 
 
 
//-----------------End here. Please do not remove this comment. Reminder: no changes outside the todo regions.
}

public static void main(String[] args)
{
removeLines("lines.txt");
int count = 0;
try (Scanner in = new Scanner(new File("lines.txt")))
{
while (in.hasNextLine())
{
in.nextLine();
count++;
}
}
catch (FileNotFoundException e)
{
e.printStackTrace();
}
System.out.println("Number of non-blank lines: " + count);
System.out.println("Expected:Number of non-blank lines: 3");
}
}