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  • Why isn't this file reading/writing program working?

    - by user320950
    This program is supposed to read files and write them. I took the file open checks out because they kept causing errors. The problem is that the files open like they are supposed to and the names are correct but nothing is on any of the text screens. Do you know what is wrong? #include<iostream> #include<fstream> #include<cstdlib> #include<iomanip> using namespace std; int main() { ifstream in_stream; // reads itemlist.txt ofstream out_stream1; // writes in items.txt ifstream in_stream2; // reads pricelist.txt ofstream out_stream3;// writes in plist.txt ifstream in_stream4;// read recipt.txt ofstream out_stream5;// write display.txt float price=' ',curr_total=0.0; int wrong=0; int itemnum=' '; char next; in_stream.open("ITEMLIST.txt", ios::in); // list of avaliable items out_stream1.open("listWititems.txt", ios::out); // list of avaliable items in_stream2.open("PRICELIST.txt", ios::in); out_stream3.open("listWitdollars.txt", ios::out); in_stream4.open("display.txt", ios::in); out_stream5.open("showitems.txt", ios::out); in_stream.close(); // closing files. out_stream1.close(); in_stream2.close(); out_stream3.close(); in_stream4.close(); out_stream5.close(); system("pause"); in_stream.setf(ios::fixed); while(in_stream.eof()) { in_stream >> itemnum; cin.clear(); cin >> next; } out_stream1.setf(ios::fixed); while (out_stream1.eof()) { out_stream1 << itemnum; cin.clear(); cin >> next; } in_stream2.setf(ios::fixed); in_stream2.setf(ios::showpoint); in_stream2.precision(2); while((price== (price*1.00)) && (itemnum == (itemnum*1))) { while (in_stream2 >> itemnum >> price) // gets itemnum and price { while (in_stream2.eof()) // reads file to end of file { in_stream2 >> itemnum; in_stream2 >> price; price++; curr_total= price++; in_stream2 >> curr_total; cin.clear(); // allows more reading cin >> next; } } } out_stream3.setf(ios::fixed); out_stream3.setf(ios::showpoint); out_stream3.precision(2); while((price== (price*1.00)) && (itemnum == (itemnum*1))) { while (out_stream3 << itemnum << price) { while (out_stream3.eof()) // reads file to end of file { out_stream3 << itemnum; out_stream3 << price; price++; curr_total= price++; out_stream3 << curr_total; cin.clear(); // allows more reading cin >> next; } return itemnum, price; } } in_stream4.setf(ios::fixed); in_stream4.setf(ios::showpoint); in_stream4.precision(2); while ( in_stream4.eof()) { in_stream4 >> itemnum >> price >> curr_total; cin.clear(); cin >> next; } out_stream5.setf(ios::fixed); out_stream5.setf(ios::showpoint); out_stream5.precision(2); out_stream5 <<setw(5)<< " itemnum " <<setw(5)<<" price "<<setw(5)<<" curr_total " <<endl; // sends items and prices to receipt.txt out_stream5 << setw(5) << itemnum << setw(5) <<price << setw(5)<< curr_total; // sends items and prices to receipt.txt out_stream5 << " You have a total of " << wrong++ << " errors " << endl; }

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  • Quickest way to write to file in java

    - by user1097772
    I'm writing an application which compares directory structure. First I wrote an application which writes gets info about files - one line about each file or directory. My soulution is: calling method toFile Static PrintWriter pw = new PrintWriter(new BufferedWriter( new FileWriter("DirStructure.dlis")), true); String line; // info about file or directory public void toFile(String line) { pw.println(line); } and of course pw.close(), at the end. My question is, can I do it quicker? What is the quickest way? Edit: quickest way = quickest writing in the file

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  • Why does C's "fopen" take a "const char *" as its second argument?

    - by Chris Cooper
    It has always struck me as strange that the C function "fopen" takes a "const char *" as the second argument. I would think it would be easier to both read your code and implement the library's code if there were bit masks defined in stdio.h, like "IO_READ" and such, so you could do things like: FILE* myFile = fopen("file.txt", IO_READ & IO_WRITE); Is there a programmatic reason for the way it actually is, or is it just historic? (i.e. "That's just the way it is.")

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  • File Output using Gforth

    - by sheepez
    As a first project I have been writing a short program to render the Mandelbrot fractal. I have got to the point of trying to output my results to a file ( e.g. .bmp or .ppm ) and got stuck. I have not really found any examples of exactly what I am trying to do, but I have found two examples of code to copy from one file to another. The examples in the Gforth documentation ( Section 3.27 ) did not work for me ( winXP ) in fact they seemed to open and create files but not write to files properly. This is the Gforth documentation example that copies the contents of one file to another: 0 Value fd-in 0 Value fd-out : open-input ( addr u -- ) r/o open-file throw to fd-in ; : open-output ( addr u -- ) w/o create-file throw to fd-out ; s" foo.in" open-input s" foo.out" open-output : copy-file ( -- ) begin line-buffer max-line fd-in read-line throw while line-buffer swap fd-out write-line throw repeat ; I found this example ( http://rosettacode.org/wiki/File_IO#Forth ) which does work. The main problem is that I can't isolate the part that writes to a file and have it still work. The main confusion is that r doesn't seem to consume TOS as I might expect. : copy-file2 ( a1 n1 a2 n2 -- ) r/o open-file throw >r w/o create-file throw r> begin pad maxstring 2 pick read-file throw ?dup while pad swap 3 pick write-file throw repeat close-file throw close-file throw ; \ Invoke it like this: s" output.txt" s" input.txt" copy-file I would be very grateful if someone could explain exactly how the open, create read and write -file words actually work, as my investigation keeps resulting in somewhat bizarre stacks. Any clues as to why the Gforth examples do not work might help too. In summary, I want to output from Gforth to a file and so far have been thwarted. Can anyone offer any help? Thank you Vijay, I think that I understand the example that you gave. However when I try to use something like this ( which I think is similar ): 0 value test-file : write-test s" testfile.out" w/o create-file throw to test-file s" test text" test-file write-line ; I get ok but nothing is put into the file, have I made a mistake? It seems that the problem was due to not flushing the relevant buffers or explicitly closing the file. Adding something like test-file flush-file throw or test-file close-file throw between write-line and ; makes it work. Thanks again Vijay for helping.

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  • Files written with FileWriter are either 32 KB, 24 KB, 16 KB, ... big or empty

    - by Bernhard V
    Hi, I read a file into a string, change the first line and then write this string into a new file. I do this through the following code (a little bit shortened): while(jspIterator.hasNext()){ String line = (String) jspIterator.next(); if (i == 0) { if (line.startsWith("bla bla") && line.endsWith("yada")) { line = line.replaceFirst("this", "that"); } } jspAsString += line; i++; } FileWriter newJspWriter = new FileWriter(newJspFile); newJspWriter.write(jspAsString); Now the files written this way are either 32, 24, 16, 8 KByte big or completely empty. When debugging I see that the String is assembled correctly. When I print the variable jspAsString to the console it also appears correct. Do you know why FileWriter behaves this way?

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  • Unable to open a file for writing

    - by asdasdas
    I am trying to write to a file. I do a file_exists check on it before I do fopen and it returns true (the file does exist). However, the file fails this code and gives me the error every time: $handle = fopen($filename, 'w'); if($handle) { flock($handle, LOCK_EX); fwrite($handle, $contents); } else { echo 'ERROR: Unable to open the file for writing.',PHP_EOL; exit(); } flock($handle, LOCK_UN); fclose($handle); Is there a way I can get more specific error details as to why this file does not let me open it for writing? I know that the filename is legit, but for some reason it just wont let me write to it. I do have write permissions, I was able to write and write over another file.

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  • Spring Integration 1.0 RC2: Streaming file content?

    - by gdm
    I've been trying to find information on this, but due to the immaturity of the Spring Integration framework I haven't had much luck. Here is my desired work flow: New files are placed in an 'Incoming' directory Files are picked up using a file:inbound-channel-adapter The file content is streamed, N lines at a time, to a 'Stage 1' channel, which parses the line into an intermediary (shared) representation. This parsed line is routed to multiple 'Stage 2' channels. Each 'Stage 2' channel does its own processing on the N available lines to convert them to a final representation. This channel must have a queue which ensures no Stage 2 channel is overwhelmed in the event that one channel processes significantly slower than the others. The final representation of the N lines is written to a file. There will be as many output files as there were routing destinations in step 4. *'N' above stands for any reasonable number of lines to read at a time, from [1, whatever I can fit into memory reasonably], but is guaranteed to always be less than the number of lines in the full file. How can I accomplish streaming (steps 3, 4, 5) in Spring Integration? It's fairly easy to do without streaming the files, but my files are large enough that I cannot read the entire file into memory. As a side note, I have a working implementation of this work flow without Spring Integration, but since we're using Spring Integration in other places in our project, I'd like to try it here to see how it performs and how the resulting code compares for length and clarity.

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  • Write problem - lossing the original data

    - by John
    Every time I write to the text file I will lose the original data, how can I read the file and enter the data in the empty line or the next line which is empty? public void writeToFile() { try { output = new Formatter(myFile); } catch(SecurityException securityException) { System.err.println("Error creating file"); System.exit(1); } catch(FileNotFoundException fileNotFoundException) { System.err.println("Error creating file"); System.exit(1); } Scanner scanner = new Scanner (System.in); String number = ""; String name = ""; System.out.println("Please enter number:"); number = scanner.next(); System.out.println("Please enter name:"); name = scanner.next(); output.format("%s,%s \r\n", number, name); output.close(); }

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  • What is the magic behind perl read() function and buffer which is not a ref ?

    - by alex8657
    I do not get to understand how the Perl read($buf) function is able to modify the content of the $buf variable. $buf is not a reference, so the parameter is given by copy (from my c/c++ knowledge). So how come the $buf variable is modified in the caller ? Is it a tie variable or something ? The C documentation about setbuf is also quite elusive and unclear to me # Example 1 $buf=''; # It is a scalar, not a ref $bytes = $fh->read($buf); print $buf; # $buf was modified, what is the magic ? # Example 2 sub read_it { my $buf = shift; return $fh->read($buf); } my $buf; $bytes = read_it($buf); print $buf; # As expected, this scope $buf was not modified

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  • Java Client-Server problem when sending multiple files

    - by Jim
    Client public void transferImage() { File file = new File(ServerStats.clientFolder); String[] files = file.list(); int numFiles = files.length; boolean done = false; BufferedInputStream bis; BufferedOutputStream bos; int num; byte[] byteArray; long count; long len; Socket socket = null ; while (!done){ try{ socket = new Socket(ServerStats.imgServerName,ServerStats.imgServerPort) ; InputStream inStream = socket.getInputStream() ; OutputStream outStream = socket.getOutputStream() ; System.out.println("Connected to : " + ServerStats.imgServerName); BufferedReader inm = new BufferedReader(new InputStreamReader(inStream)); PrintWriter out = new PrintWriter(outStream, true /* autoFlush */); for (int itor = 0; itor < numFiles; itor++) { String fileName = files[itor]; System.out.println("transfer: " + fileName); File sentFile = new File(fileName); len = sentFile.length(); len++; System.out.println(len); out.println(len); out.println(sentFile); //SENDFILE bis = new BufferedInputStream(new FileInputStream(fileName)); bos = new BufferedOutputStream(socket.getOutputStream( )); byteArray = new byte[1000000]; count = 0; while ( count < len ){ num = bis.read(byteArray); bos.write(byteArray,0,num); count++; } bos.close(); bis.close(); System.out.println("file done: " + itor); } done = true; }catch (Exception e) { System.err.println(e) ; } } } Server public static void main(String[] args) { BufferedInputStream bis; BufferedOutputStream bos; int num; File file = new File(ServerStats.serverFolder); if (!(file.exists())){ file.mkdir(); } try { int i = 1; ServerSocket socket = new ServerSocket(ServerStats.imgServerPort); Socket incoming = socket.accept(); System.out.println("Spawning " + i); try { try{ if (!(file.exists())){ file.mkdir(); } InputStream inStream = incoming.getInputStream(); OutputStream outStream = incoming.getOutputStream(); BufferedReader inm = new BufferedReader(new InputStreamReader(inStream)); PrintWriter out = new PrintWriter(outStream, true /* autoFlush */); String length2 = inm.readLine(); System.out.println(length2); String filename = inm.readLine(); System.out.println("Filename = " + filename); out.println("ACK: Filename received = " + filename); //RECIEVE and WRITE FILE byte[] receivedData = new byte[1000000]; bis = new BufferedInputStream(incoming.getInputStream()); bos = new BufferedOutputStream(new FileOutputStream(ServerStats.serverFolder + "/" + filename)); long length = (long)Integer.parseInt(length2); length++; long counter = 0; while (counter < length){ num = bis.read(receivedData); bos.write(receivedData,0,num); counter ++; } System.out.println(counter); bos.close(); bis.close(); File receivedFile = new File(filename); long receivedLen = receivedFile.length(); out.println("ACK: Length of received file = " + receivedLen); } finally { incoming.close(); } } catch (IOException e){ e.printStackTrace(); } } catch (IOException e1){ e1.printStackTrace(); } } The code is some I found, and I have slightly modified it, but I am having problems transferring multiple images over the server. Output on Client: run ServerQueue.Client Connected to : localhost transfer: Picture 012.jpg 1312743 java.lang.ArrayIndexOutOfBoundsException Connected to : localhost transfer: Picture 012.jpg 1312743 Cant seem to get it to transfer multiple images. But bothsides I think crash or something because the file never finishes transfering

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  • VB.NET 2008, Windows 7 and saving files

    - by James Brauman
    Hello, We have to learn VB.NET for the semester, my experience lies mainly with C# - not that this should make a difference to this particular problem. I've used just about the most simple way to save a file using the .NET framework, but Windows 7 won't let me save the file anywhere (or anywhere that I have found yet). Here is the code I am using to save a text file. Dim dialog As FolderBrowserDialog = New FolderBrowserDialog() Dim saveLocation As String = dialog.SelectedPath ... Build up output string ... Try ' Try to write the file. My.Computer.FileSystem.WriteAllText(saveLocation, output, False) Catch PermissionEx As UnauthorizedAccessException ' We do not have permissions to save in this folder. MessageBox.Show("Do not have permissions to save file to the folder specified. Please try saving somewhere different.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error) Catch Ex As Exception ' Catch any exceptions that occured when trying to write the file. MessageBox.Show("Writing the file was not successful.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error) End Try The problem is that this using this code throws an UnauthorizedAccessException no matter where I try to save the file. I've tried running the .exe file as administrator, and the IDE as administrator. Is this just Windows 7 being overprotective? And if so, what can I do to solve this problem? The requirements state that I be able to save a file! Thanks.

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  • Opening a file in c++ by using a string array of adress

    - by muhammad-aslam
    Hello guYz plz help me out in making it possible to open the files by the adress provided in an array of strings......... a way to open file is as given below... ifstream infile; infile.open("d:\aslam.txt"); but how can i open file providing an array of string as an adress of file..... like this infile.open(arr[i]); (but its not working) plz help me.........

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  • What is the easiest way to loop through a folder of files in C#?

    - by badpanda
    I am new to C# and am trying to write a program that navigates the local file system using a config file containing relevant filepaths. My question is this: What are the best practices to use when performing file I/O (this will be from the desktop app to a server and back) and file system navigation in C#? I know how to google, and I have found several solutions, but I would like to know which of the various functions is most robust and flexible. As well, if anyone has any tips regarding exception handling for C# file I/O that would also be very helpful. Thanks!!! badPanda

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  • Add HTML Id's to tags in .aspx file

    - by slandau
    So I'm writing an app that lets the user select a folder, it gets all the .aspx files in that folder, and lets the users check off which ones they want to add HTML ID's to. Then they click start, and this runs private void btnStart_Click(object sender, EventArgs e) { for (int i = 0; i < listFiles.CheckedItems.Count; i++) { } } It loops through all the selected file names. How do I open each of these .aspx files in the background, and go through them and add the id="thisItemId" attribute to each tag that's like a , , , , , etc....

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  • What is the fastest way for reading huge files in Delphi?

    - by dummzeuch
    My program needs to read chunks from a huge binary file with random access. I have got a list of offsets and lengths which may have several thousand entries. The user selects an entry and the program seeks to the offset and reads length bytes. The program internally uses a TMemoryStream to store and process the chunks read from the file. Reading the data is done via a TFileStream like this: FileStream.Position := Offset; MemoryStream.CopyFrom(FileStream, Size); This works fine but unfortunately it becomes increasingly slower as the files get larger. The file size starts at a few megabytes but frequently reaches several tens of gigabytes. The chunks read are around 100 kbytes in size. The file's content is only read by my program. It is the only program accessing the file at the time. Also the files are stored locally so this is not a network issue. I am using Delphi 2007 on a Windows XP box. What can I do to speed up this file access?

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  • Read a specific range of lines from a file using c

    - by James Joy
    I have the following content in a file: hhasfghgsafjgfhgfhjf gashghfdgdfhgfhjasgfgfhsgfjdg jfshafghgfgfhfsghfgffsjgfj . . . . . startread hajshjsfhajfhjkashfjf hasjgfhgHGASFHGSHF hsafghfsaghgf . . . . . stopread . . . . . . jsfjhfhjgfsjhfgjhsajhdsa jhasjhsdabjhsagshaasgjasdhjk jkdsdsahghjdashjsfahjfsd I need to read the lines from the next line of startread till the previous line of stopread using a c code and store it to a string variable(of course with a \n for every line breaks). How can i achieve this? I have used fgets(line,sizeof(line),file); but it starts reading from the beginning. I don't have the exact line number to start and stop reading since the file is written by another C code. But there are these identifiers startread and stopread to identify whereto start reading. Operating platform is linux. Thanks in advance.

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  • How to read from database and write into text file with C#?

    - by user147685
    How to read from database and write into text file? I want to write/copy (not sure what to call) the record inside my database into a text file. One row record in database is equal to one line in the text file. I'm having no problem in database. For creating text file, it mentions FileStream and StreamWriter. Which one should I use?

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  • Search a string in a file and write the matched lines to another file in Java

    - by Geeta
    For searching a string in a file and writing the lines with matched string to another file it takes 15 - 20 mins for a single zip file of 70MB(compressed state). Is there any ways to minimise it. my source code: getting Zip file entries zipFile = new ZipFile(source_file_name); entries = zipFile.entries(); while (entries.hasMoreElements()) { ZipEntry entry = (ZipEntry)entries.nextElement(); if (entry.isDirectory()) { continue; } searchString(Thread.currentThread(),entry.getName(), new BufferedInputStream (zipFile.getInputStream(entry)), Out_File, search_string, stats); } zipFile.close(); Searching String public void searchString(Thread CThread, String Source_File, BufferedInputStream in, File outfile, String search, String stats) throws IOException { int count = 0; int countw = 0; int countl = 0; String s; String[] str; BufferedReader br2 = new BufferedReader(new InputStreamReader(in)); System.out.println(CThread.currentThread()); while ((s = br2.readLine()) != null) { str = s.split(search); count = str.length - 1; countw += count; //word count if (s.contains(search)) { countl++; //line count WriteFile(CThread,s, outfile.toString(), search); } } br2.close(); in.close(); } -------------------------------------------------------------------------------- public void WriteFile(Thread CThread,String line, String out, String search) throws IOException { BufferedWriter bufferedWriter = null; System.out.println("writre thread"+CThread.currentThread()); bufferedWriter = new BufferedWriter(new FileWriter(out, true)); bufferedWriter.write(line); bufferedWriter.newLine(); bufferedWriter.flush(); } Please help me. Its really taking 40 mins for 10 files using threads and 15 - 20 mins for a single file of 70MB after being compressed. Any ways to minimise the time.

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  • Java how to copy part of a file

    - by user3479074
    I have to read a file and depending of the content of the last lines, I have to copy most of its content into a new file. Unfortunately I didn't found a way to copy first n lines or chars of a file in java. The only way I found, is copying the file using nio FileChannels where I can specifiy the length in bytes. However, therefore I would need to know how many bytes the stuff I read needed in the source-file. Does anyone know a solution for one of these problems?

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