Question

How can I create Loops and Files on Java?

• Create a program that reads a list of names from a source file and writes those names to a CSV file. The source file name and target CSV file name should be requested from the user • The source file can have a variable number of names so your program should be dynamic enough to read as many names as needed • When writing your CSV file, the first row (header rowl should be "Number Name • The final CSV should have the header row and arow with the sequential number, name read. . The program should display an error message if the source file doesn't exist • If the destination file exists the program should warn the user and prompt the user if they want to overwrite the existing file(Y/N). The user should be prompted until they enter Y for yes to overwrite, or enter a unique name after answering N for the overwrite prompt Source file example: John Peter Jane Mary Evelyn Daniel New CSV file example: Number Name 1. John 2 Peter 4 Mary S Evelyn Daniel Example Scenario 1 - Normal Em suolen source.txt

Answer 1

import java.io.File; //getb properties of file
import java.io.FileWriter; //write the data to the file
import java.io.IOException;
import java.io.FileNotFoundException;
import java.util.Scanner; //read the data from input stream i.e,keyboard
public class CSVFileWriter
{
public static void writeDataToCSVFile(File fileSource,File fileDestination) throws IOException,FileNotFoundException
{
   Scanner fileInput=new Scanner(fileSource);
   FileWriter fileOutput=new FileWriter(fileDestination);
   int n=1;
   fileOutput.write("Number,Name\n");
   while(fileInput.hasNextLine())//read line by line data from file
   {
      fileOutput.write(n+","+fileInput.nextLine()+"\n");
      ++n;
   }
   fileInput.close();
   fileOutput.close();
   System.out.println("Your file is ready!");
}
public static void main(String[] args) throws IOException,FileNotFoundException
{
   String source,destination;
   Scanner input=new Scanner(System.in);
   System.out.print("Enter source file name: ");
   source=input.nextLine();
   System.out.print("Enter destination file name: ");
   destination=input.nextLine();
   File fileSource=new File(source);
   File fileDestination=new File(destination);
   if(!fileSource.exists()) //check if file exists or not
   System.out.println("Source file doesn't exist!");
   else if(fileDestination.exists()) //destination file already exists
   {
     char status;
     System.out.print("Target file already exists.Overwrite existing file?(Y/N):");
     status=input.next().charAt(0);
     while(status=='N')
     {
         input.nextLine();
         System.out.print("Enter destination file name: ");
         destination=input.nextLine();
         fileDestination=new File(destination);
         if(fileDestination.exists()) //if file exists
         {
          System.out.print("Target file already exists.Overwrite existing file?(Y/N):");
          status=input.next().charAt(0);
         }
         else
         break; //file does not exists
       }
     writeDataToCSVFile(fileSource,fileDestination); //write data to csv file
   }
   else
   writeDataToCSVFile(fileSource,fileDestination);
}   
}

Output

destination.csv