File Name from User Input

The following program (a version of a previous example) prompts the user for both the names of the input file and the output file.

import java.util.Scanner;
import java.io.*;

class NamedFileInOut
{
  public static void main (String[] args) throws IOException
  { 
    int num, square;    

    // Scanner for user input
    Scanner user = new Scanner( System.in ); 
    String  inputFileName, outputFileName;

    // prepare the input file
    System.out.print("Input File Name: ");
    inputfileName = user.nextLine().trim();
    File input = new File( fileName );      
    Scanner scan = new Scanner( input );      

    // prepare the output file
    System.out.print("Output File Name: ");
    outputfileName = user.nextLine().trim();
    File output = new File( fileName );      
    PrintStream  print = new PrintStream( output );      

    // processing loop
    while( scan.hasNextInt() )    
    {
      num = scan.nextInt();
      square = num * num ;      
      print.println("The square of " + num + " is " + square);
    }

    // close the output file
    print.close();
  }
}

This program can be used as the basis for many others. Several of the programming exercises can be done by copying this program and making small changes to the processing loop.