Computer Science Canada TextInputFile & TextOutputFile help needed |
Author: | C [ Tue Mar 09, 2010 8:57 pm ] |
Post subject: | TextInputFile & TextOutputFile help needed |
I have a project due soon and it uses a method called TextInputFile & TextOutputFile, and I am having trouble deleting an existing value from the text file created. For example, I have a text file that have an integer 6 and a String "Hello" stored and I want to delete them both and replace them with another integer and another String. Any ideas on how to do this ? |
Author: | facultyofmusic [ Fri Mar 12, 2010 5:43 pm ] |
Post subject: | Re: TextInputFile & TextOutputFile help needed |
There's no need to delete the data. Just over write it. When you make a new PrintWriter to a file, it equals deleting all contents and rewriting it from the beginning. |
Author: | Daniel Lee Wilkes [ Thu Apr 15, 2010 9:36 pm ] |
Post subject: | Re: TextInputFile & TextOutputFile help needed |
Hey, I know this is kind of old, but I have a very relevant question.. I want to make a program that stores data such as a high score in a text file. So far I have no problem with that, but when ever I re-run the program, that file it totally overridden. This sounds like what facultyofmusic was describing, but I don't know what to do to not do that. Here is some coding example: Quote: /* write data to file */
System.out.print("Enter the file name for storing names and grades: "); fileName = input.nextLine(); System.out.print("How many students? "); numStu = input.nextInt(); try { dataFile = new File(fileName); out = new FileWriter(dataFile); writeFile = new BufferedWriter(out); for (int i = 0; i < numStu; i++) { System.out.print("Enter student name: "); stuName = input.next(); System.out.print("Enter test score: "); score = input.next(); writeFile.write(stuName); writeFile.newLine(); writeFile.write(score); writeFile.newLine(); } writeFile.close(); out.close(); System.out.println("Data written to file."); } catch (IOException e) { System.out.println("Problem writing to file."); System.err.println("IOException: " + e.getMessage()); } I assume most programmers can fill in the blanks, if not, I will paste the whole program. Thank you in advance for the help. P.S. I am not assuming that the text file already exists. It needs to be created if it isn't already there (which is a simple if statement). P.P.S. I have no idea what part of the code actually makes the file. I use <fileObject>.creatNewFile() but this program doesn't have that and it runs just fine. I got it from an example from my teacher who got it from a resource book. |
Author: | Insectoid [ Fri Apr 16, 2010 9:51 am ] |
Post subject: | RE:TextInputFile & TextOutputFile help needed |
It's supposed to be overwritten. If you want to save the data, you need to have a reader load the content into RAM, then write to it. If the file doesn't exist, Java will create it. No need for a conditional. |