writing to an output...

**lairel** · February 28th, 2011, 06:56 PM

I wrote this code to access a file for input, but now i need to make the input into an output converting all characters to upper.

import java.util.Scanner;
import java.io.*;
 
public class IoDemo
{
	public static void main(String[] args) throws IOException
	{
		//Create scanner object
		Scanner keyboard = new Scanner(System.in);
 
		//Get file name
		System.out.println("Enter the name of the input file: ");
		String filename = keyboard.nextLine();
 
		//open the file
		File file = new File(filename);
		Scanner inputFile = new Scanner(file);
 
		//Close the file
		inputFile.close();
 
	}
}

the planned output should go:

Enter the name of the input file: quotations.txt
Enter the name of the output file: allupper.txt

thats all that the program will display but it turns the text in the input file into a new output file that is now all upper.
How do I write the code to directly create a new text file while turning all the text into uppercase?

**lairel** · February 28th, 2011, 10:56 PM

import java.util.Scanner;
import java.io.*;
 
public class IoDemo
{
	public static void main(String[] args) throws IOException
	{
		//Create scanner object
		Scanner keyboard = new Scanner(System.in);
 
		//Get file name
		System.out.print("Enter the name of the input file: ");
		String filename = keyboard.nextLine();
 
		//open the file
		File file = new File(filename);
		Scanner inputFile = new Scanner(file);
 
		//create new file
		System.out.print("Enter the name of the output file: ");
		String newFile = keyboard.nextLine();
 
		//open new file
		PrintWriter outputFile = new PrintWriter(newFile);
 
		//convert to upper
		String toUpper = filename.toUpperCase();
		outputFile.println(toUpper);
 
		//Close the file
		inputFile.close();
		outputFile.close();
 
	}
}

this is what i have, but it isn't working correctly, instead of converting the contents of the input file into uppercase and then putting it in the new output file, it converts the input of the file name into uppercase in the output file.

**helloworld922** · February 28th, 2011, 11:34 PM

		//convert to upper
		String toUpper = filename.toUpperCase();
		outputFile.println(toUpper);

That's because you're converting the filename to upper case rather than the data inside the file.

Read the text in from the file first, then convert it to upper case and write it back out.

To read in from a file:

StringBuilder fileTextBuilder = new StringBuilder();
while(inputFile.hasNext())
{
    fileText.append(inputFile.nextLine());
    if(inputFile.hasNext())
    {
        fileText.append("\n");
    }
}
String fileText = fileTextBuilder.toString();
// TODO: convert fileText to upper case
// TODO: write fileText out to the new file

**lairel** · March 1st, 2011, 03:22 AM

i'm still getting errors, this is what i have so far

   import java.util.Scanner;
   import java.io.*;
 
   public class IoDemo
   {
      public static void main(String[] args) throws IOException
      {
      //Create scanner object
         Scanner keyboard = new Scanner(System.in);
 
      //Get file name
         System.out.print("Enter the name of the input file: ");
         String filename = keyboard.nextLine();
 
      //open the file
         File file = new File(filename);
         Scanner inputFile = new Scanner(file);
 
      //create new file
         System.out.print("Enter the name of the output file: ");
         String newFile = keyboard.nextLine();
 
      //open new file
         PrintWriter outputFile = new PrintWriter(newFile);
 
      //convert to upper
         StringBuilder fileTextBuilder = new StringBuilder();
         while(inputFile.hasNext())
         {
            fileTextBuilder.append(inputFile.nextLine());
            if(inputFile.hasNext())
            {
               fileTextBuilder.append("\n");
            }
         }
 
        String output = fileTextBuilder.toUpperCase();
        outputFile.println(output);
 
         String fileText = fileTextBuilder.toString();
      	outputFile.flush();
 
      //Close the file
         inputFile.close();
         outputFile.close();
 
      }
   }

symbol : method toUpperCase()
location: class java.lang.StringBuilder
String output = fileTextBuilder.toUpperCase();
^
1 error

**JavaPF** · March 1st, 2011, 04:27 AM

The issue is with:

String output = fileTextBuilder.toUpperCase();

The method toUpperCase() is undefined for the type StringBuilder

I can see you have took onboard what helloworld922 said but you need to change the code slightly.

Try this:

         String fileText = fileTextBuilder.toString();
         String output = fileText.toUpperCase();
 
         outputFile.println(output);
      	 outputFile.flush();

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