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Thread: Input/Output file help

  1. #1
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    Default Input/Output file help

    Assignment:
    Uppercase File Converter
    Write a program that asks the user for the names of two files. The first file should be opened for reading and the second file should be opened for writing. The program should read the contents of the first file, change all characters to uppercase, and store the results in the second file. The second file will be a copy of the first file, except that all the characters will be uppercase. Use Notepad or another text editor to create a simple file that can be used to test the program.

    Notepad:
    Frankie owned a
    ferocious feline named
    Freddy as a pet.
    Freddy was funny and
    furry.
    His fur is bright red
    with black stripes.

    /*
     * To change this template, choose Tools | Templates
     * and open the template in the editor.
     */
     
    package uppercasefileconverter;
    import java.util.Scanner;
    import java.io.*;
     
    /**
     *
     * @author uuuuuuu
     */
    public class Main {
     
        /**
         * @param args the command line arguments
         */
        public static void main(String[] args) throws IOException {
            Scanner keyboard = new Scanner(System.in);
     
            String filename1;
            String filename2;
     
            System.out.println("Enter name of file 1:");
            filename1 = keyboard.nextLine();
     
            System.out.println("Enter name of file 2:");
            filename2 = keyboard.nextLine();
     
            File file1 = new File(filename1);
            Scanner inputFile = new Scanner(file1);
            inputFile.close();
     
            PrintWriter outputFile = new PrintWriter(filename2);
            outputFile.println(filename1.toUpperCase());  
            outputFile.close();
        }
     
    }

    The file names that I will be using are:
    testfile.txt
    testfileCopy.txt

    What do I need to fix in the code?
    Error pops up because of throws IOException.
    run:
    Enter name of file 1:
    testfile.txt
    Enter name of file 2:
    testfileCopy.txt
    Exception in thread "main" java.io.FileNotFoundException: testfile.txt (The system cannot find the file specified)
            at java.io.FileInputStream.open(Native Method)
            at java.io.FileInputStream.<init>(FileInputStream.java:106)
            at java.util.Scanner.<init>(Scanner.java:636)
            at uppercasefileconverter.Main.main(Main.java:32)
    Java Result: 1
    BUILD SUCCESSFUL (total time: 1 minute 40 seconds)
    Last edited by Plural; October 23rd, 2010 at 07:06 PM.


  2. #2
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    Default Re: Input/Output file help

    Quote Originally Posted by Plural View Post
    Assignment:
    Uppercase File Converter
    Write a program that asks the user for the names of two files. The first file should be opened for reading and the second file should be opened for writing. The program should read the contents of the first file, change all characters to uppercase, and store the results in the second file. The second file will be a copy of the first file, except that all the characters will be uppercase. Use Notepad or another text editor to create a simple file that can be used to test the program.

    Notepad:
    Frankie owned a
    ferocious feline named
    Freddy as a pet.
    Freddy was funny and
    furry.
    His fur is bright red
    with black stripes.

    /*
     * To change this template, choose Tools | Templates
     * and open the template in the editor.
     */
     
    package uppercasefileconverter;
    import java.util.Scanner;
    import java.io.*;
     
    /**
     *
     * @author uuuuuuu
     */
    public class Main {
     
        /**
         * @param args the command line arguments
         */
        public static void main(String[] args) throws IOException {
            Scanner keyboard = new Scanner(System.in);
     
            String filename1;
            String filename2;
     
            System.out.println("Enter name of file 1:");
            filename1 = keyboard.nextLine();
     
            System.out.println("Enter name of file 2:");
            filename2 = keyboard.nextLine();
     
            File file1 = new File(filename1);
            Scanner inputFile = new Scanner(file1);
            inputFile.close();
     
            PrintWriter outputFile = new PrintWriter(filename2);
            outputFile.println(filename1.toUpperCase());  
            outputFile.close();
        }
     
    }

    The file names that I will be using are:
    testfile.txt
    testfileCopy.txt

    What do I need to fix in the code?
    Error pops up because of throws IOException.
    run:
    Enter name of file 1:
    testfile.txt
    Enter name of file 2:
    testfileCopy.txt
    Exception in thread "main" java.io.FileNotFoundException: testfile.txt (The system cannot find the file specified)
            at java.io.FileInputStream.open(Native Method)
            at java.io.FileInputStream.<init>(FileInputStream.java:106)
            at java.util.Scanner.<init>(Scanner.java:636)
            at uppercasefileconverter.Main.main(Main.java:32)
    Java Result: 1
    BUILD SUCCESSFUL (total time: 1 minute 40 seconds)
    Your file doesn't exist apparently. You told it to throw that exception if there was no file of that name.


    I think I see the problem. You're having them create a File. That file is empty. You're scanning nothing.
    Last edited by javapenguin; October 23rd, 2010 at 07:21 PM.

  3. #3
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    Default Re: Input/Output file help

    Quote Originally Posted by javapenguin View Post
    Your file doesn't exist apparently. You told it to throw that exception if there was no file of that name.
    I have it on my computer, but it somehow can't find it.
    Where should I be saving it?

  4. #4
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    Default Re: Input/Output file help

    Also, you closed the input file. It won't give any more input to be scanned after the .close.

    You can certainly, I think, tell it to open a File by having the user give it a name, but if it doesn't match the name of your input file, it'll throw the FileNotFoundException. Also, you never read anything from it. You just close it. Or so it seems from your code. Then you ask it to output it to another File, and you output to that one merely the name that the user gave for fileOne in upper case.

    Also, you never put anything from that name. Unless the file already exists.

    However, it won't read anything unless you do something like:

    while (inputFile.hasNext())


    Then you would do something like this:

    String s = inputFile.nextLIne();

    Then later, you'd have to write it all back.
    Last edited by javapenguin; October 23rd, 2010 at 07:35 PM.

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