C++ :: Create File With Fstream?
Feb 18, 2014
For some unknown reason when i try the following code it doesn't create a file. (the program will simply get two inputs from the user and then use http to obtain the html/php text and then output it to a file)
code:
#include <SFML/Network.hpp>
#include <iostream>
using std::cout;
[Code].....
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Apr 14, 2013
I'm working on a program which creates data and saves it into blocks (different files), then reloads and converts it all. the .ftl file saves properly, but for some unknown reason, it won't let me open it for input after.
Here's the significant code:
#include <iostream>
#include <fstream>
#include <string>
#include <sstream>
stringstream filename;
stringstream newfilename;
string Filename;
[Code] ....
setblock will typically = 3, but for testing purposes is set to 1. this really has me confused. the compiler i'm using is Dev-C++ 5.2.0.1 on xp. i have tried pausing the program after the output file is closed, confirming the file has been created in the proper directory before continuing but still fails the .is_open() check.
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Feb 14, 2014
So, I am making a name-database-type-thing and I want the user to be able to enter there own file. Like, here:
string fileName;
string name;
cout<<"What is your file name?"<<endl;
getline(cin, fileName);
ifstream nameFile(fileName);
getline(cin, name);
nameFile<<"Name: "<<endl;
Well, that last part is in a loop, so you can enter an unlimited number of names to the .txt file.
So, it won't let me use the string in ifstream. How can I fix this? This maybe unclear, so if it is just say so and I will edit it.
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Oct 16, 2013
I have a file of data where each line consists of 4 parameters (degree, alpha, beta and x) and a value corresponding to these, organized in increasing order of the parameters. Here's the test file I'm using:
0 1 1 0.5 3.5
1 1 1 -0.5 -0.5
1 2 0 0.2 4.5
1 3 0 0.2 -4.5
2 0 0 1.5 2.1
2 1 0 0 5.6
My code is supposed to look for a certain set of parameters (currently set to 1 2 1 1.5, which is not contained in the file) and its value. If it's there (i.e. the file contains the value for the right parameters) the program is done. If not it should calculate the value using a function JacobiPoly() and insert the wanted parameters and corresponding value in the appropriate place in the file.
I have a code in which I think everything works except the writing to file. I use an fstream so I can both read and write and open it with ios::out||ios::in. I'm also aware I need something similar to fseek in between input and output but according to [URL] .... reading and writing to the same file using the same fstream, seekp() should suffice. I'm using seekp(), but the output (in the form inout << (...)) doesn't work.
Here's the code:
fstream inout;
inout.open("inouttest.dat", ios::out | ios::in);
int degree=1, readDeg;
double alpha=2, beta=1, x=1.5, value, readAlpha, readBeta, readX, readVal;
bool foundVal=false;
streampos beforeRead=(streampos)0;
[Code] ....
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Sep 7, 2012
I want to edit the contents of a file using fstream, but none of the modes in the fstream constructor work for me.
If I use ios::trunc, then the whole file is deleted - but I want to retain the contents and edit it. If I use ios::app, then I can only add data to the end of the file - but I want to edit the data in the middle of the file. If I use ios::ate, then the whole file is deleted again, similar to ios::trunc.
How can I create an fstream object without deleting the contents of the file, whilst still being able to move the pointer arbitrarily around in the file with seekp() (and not just placing it at the end as with ios::app)?
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Nov 9, 2012
I did some of the projects using STL container and it is pretty much efficient to retrieve the data's information quickly (i.e. sets, sets & maps). I read many C++ OOP book and none of them make me clear about the Link Between (STL) Container and (Fstream) File I/O. Can they link together ?
I am going to design a small Library Book Management Project. I am planning to develop it using the STL Algorithms & containers. Objective of this project is to keeping the records of books issued and deposited by students in a particular date. User will be given a facility to retrieve student's information, book information and he/she can modify/update specific book's, student's information by changing issue date, deposited date, Book's publication etc.
My intention is to create a File I/O where user can input & update/modify daily transaction inside the file called (xx.dat) file in project directory. Is it possible to create 'set' container inside the file (xx.dat) ? Or, It's impossible ? Or, do i have to do this in other way?
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Jul 25, 2013
How to forbid file replacing in fstream library for C++?
#include <iostream>
#include <fstream>
using namespace std;
int main() {
ofstream myfile;
[Code] ....
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Dec 16, 2014
I'm trying to make a simple phonebook app that can show contacts, add, and delete. I'm pretty new to C++ and fstream functions, deleting a line in my bool erase() function?
#include <iostream>
#include <conio.h>
#include <string>
[Code].....
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Jan 20, 2013
other posts talk about the fopen function and don't really give any solutions to this the var that has the file path is a char* and has been converted from a system::string^ it is completely valid when I paste it in windows bar.
Code:
private: System::Void button3_Click(System::Object^ sender, System::EventArgs^ e) {
if(textBox1->Text[0] == (char)'' || textBox2->Text[0] == (char)''){
MessageBox::Show("Please select a valid m3u and path", "Problem",
MessageBoxButtons::OK, MessageBoxIcon::Exclamation);
[Code]....
it crashes right at the pile.open() function call when I put breakpoints in it says , debug assertion failed and shows me the fclose.c file location and Expression: (stream != NULL)
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Jul 9, 2014
fstream ifs;
ifs.open ("data.str", ios::binary | ios:ut);
char *data1 = "data1";
char *data2 = "data2";
ifs.write(data1, strlen(data1));
ifs.write(data2, strlen(data2));
when i this,data2 is not going under data1, i thought each write starts on a new line?
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Jan 15, 2014
I need to a simple example for writing class' objects to a text file using fstream , I tried to search the forums and I found binary examples but not for to a text file.
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Nov 20, 2012
I'm using Visual C++ 6.0 and I'm trying to use fstream to open and read a file that is created only during runtime. This file is written by another function running on another thread, and my program will keep trying to "open" the file until it can be opened, i.e. after it's created, then read 3 numbers from it and execute the rest of its code.
The file test.txt has the content
Code:
1
3
4
My program that polls and opens the file is as follows:
Code:
ifstream fin;
std::string tfile, snum1, snum2, snum3;
long int num2, num3;
tfile.assign(argv[1]);
printf("Begin prog %s
", tfile.c_str());
[code]....
I executed the program by
Code: test_prog.exe "C: est.txt"
and waited about 3 seconds before putting the test.txt file into C:
My output was
Code:
Begin prog C: est.txt
Cannot open file C: est.txt
Cannot open file C: est.txt
Cannot open file C: est.txt
Cannot open file C: est.txt
Cannot open file C: est.txt
Cannot open file C: est.txt
fin is open
snum1 =
num2 = 0 num3 = 0
End of prog
The test.txt file disappears after I refresh the C: folder.
So the values for snum1, num2 and num3 are all wrong, as if the file was not read correctly.
If I put a while fin.good() loop after printf("fin is open "); for that entire block (until printing the values of num2 and num3), then I get
Code:
Begin prog C: est.txt
Cannot open file C: est.txt
Cannot open file C: est.txt
Cannot open file C: est.txt
Cannot open file C: est.txt
Cannot open file C: est.txt
Cannot open file C: est.txt
fin is open
End of prog
How can I correctly read a file that is only created during runtime?
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Dec 31, 2014
I would like to copy one bmp file to another using plain fstream (none 3-rd party library). I've managed to come up with something but I keep getting error:
Unhandled exception at 0x504A3442 (msvcr120d.dll) in ConsoleApplication1.exe: 0xC0000005: Access violation reading location 0x00380000.
when i try to write the content of the bmp files not the header, namely error occurs in this line:
Code : ofs_differential.write((char*)&picture, (bfh_warm.bfSize - bfh_warm.bfOffBits));
Also i am not sure if i am doing it in a right way, meaning that even after solving this error i will copy the bmp file successfully.
Code:
// ConsoleApplication1.cpp : Defines the entry point for the console application.
//
#include "stdafx.h"
#include <iostream>
#include <fstream>
using namespace std;
struct BITMAPfileHEADER {
unsigned short bfType;
[code]....
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Apr 28, 2014
So I have a small program which is supposed to write and read multiple objects from a file, but for some reason it doesn't write the information when I use "fstream" to create the object from the fstream class, but it does when I use "ofstream". Also, it doesn't read the information from the file no matter if I use "fstream" or "ifstream". I watched a video where this exact code worked just fine, but it just won't work when I run it. I'm using Dev C++ 4.9.9.2, I don't know if that has anything to do with it, I also tried it with Code::Blocks, didn't work either.
Here's the code.
#include <iostream>
#include <fstream>
using namespace std;
class Person
[Code].....
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Apr 10, 2014
I need to create a project that create a automated backup of a file.
i will get the file from C:/Folder/file.exe and move for a other created folder, but.. in every time that user make this backup, a folder will be created with year, month and date, like: C/Folder2/2014/April/16:42/file.exe.
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Apr 4, 2014
I want to design a class that will open a text file and manipulate the data in it. And I have to use all these functions from fstream like ifstream, ofstream, seekg etc. The problem is that I can't get the first part to work (getting my constructor to open the file using ifstream). I've posted my test.h file below.
#ifndef TEST_H_INCLUDED
#define TEST_H_INCLUDED
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
using std::ifstream;
class Test {
[Code] ....
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Mar 15, 2013
The Objective Of This Program Is To Create A File To Write Text And Read Back The File Content. To Do That I Have Made Two Function writeFile() To Write And readFile() To Read.The readFile() function works just fine but writeFile() doesn't.
How writeFile() function Works? when writeFile() function Execute It Takes Characters User Type And When Hit Enter(ASC|| 10) It Ask "More?(Y/N)" That Means What User Want? Want To Go Next Line Or End Input?
If "Y" Than Inputs Are Taken From Next Line Else Input Ends.
But The Problem Is When Program Encounters ch==10 It Shows "More?(Y/N)" And Takes Input In cmd variable.If cmd=='Y' I Mean More From Next Line Than It Should Execute Scanf Again To Take ch I Mean User Input.But Its Not!!! Its Always Showing "More?(Y/N)" Again And Again Like A Loop.
Code:
#include <stdio.h>
void writeFile(void);
void readFile(void);
int main(){
[Code].....
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Feb 2, 2013
I'm trying to input a html file and copy everything from that file to a new html file with some changes. I need to read the html file word by word and compare them to a file with some keywords. If a keyword matches a word in the html file then it will add italic tags around that word in the output html file. As it is now it doesn't output anything.
Logically I want to read a word from the html file and then compare it to every keyword and output the result.
fileIn = original html file
keyword = keywords file
outFile = html file writing to
std::string str;
std:: string word;
[Code]...
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Mar 21, 2015
Ive used a similar approach to extract data from a txt file before, however now it seems to crash when i get to the load, below is the code with a NOTE next to where it crashes. This is homework so no code but just information on why it was working for one dataset but not his new one.
/*
The purpose of this program is to read in data and sort with selection and insertion sort. It will read data from file and write to a new file the sorted data
*/
#include <iostream>
#include <fstream>
using namespace std;
bool openFile(ifstream&);
[code].....
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Jul 6, 2013
I want my function to take 'fstream' object as an input, so the program looks like this:
Code:
#include <fstream>
using namespace std;
void test(fstream a){
a.open("test2.txt");
a << "123" << endl
[Code] ....
But I get error: 'std::ios_base::ios_base(const std::ios_base&)' is private|
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Feb 17, 2015
I am interested in creating a file of a given size and then randomly accessing the file to populate it. Is there a way to quickly create, for instance, a 4 GByte file in C++, initially populated with garbage?
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Jul 14, 2012
I have a folder "pics" in g: drive. There I want to create some text.txt file. Thus, the final path is "g:pics ext.txt".
How can I do that?
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Oct 10, 2014
How do you create a save file for a game, that is not a separate file? Specifically I am using code::blocks and sfml 2.1 to make a game and it saves to a text file at the moment. My problem is that it is very easy to modify the text file, and it is annoying to have to copy and paste several files if you want to use a copy of the game. I have a feeling that it may be to do with resource files, but I'm not exactly sure how to get these to work or whether you can modify them dynamically.
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Feb 7, 2014
I've been having this odd problem when I write a file byte by byte, when I write a byte (dec)10 it adds a (dec)13 in front of it, and as far as I can tell, this is the only byte value that does this.
and most annoyingly, I can't read that (dec)13 with fstream, the only reason I know it's adds it, is because I used an external hex editor.
here is the code that causes the problem:
Code:
#include <fstream>
using namespace std;
int main()
{
[Code]...
but the output file reads '0D 0A' (that's in hex, '13 10' in decimal) when viewed in a hex editor. no other number (that I've tried) adds that extra 13.
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Jun 10, 2013
If the filename below is a directory, then the following loop goes to infinite.
std::ifstream in;
in.open(filename, std::ifstream::in);
if(in.fail()) return;
[Code].....
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Jan 1, 2014
Im about to program a RPG and, of course, the player has got an inventory. The items in this inventory are stored in a linked list and have IDs in form of strings.
player.cpp: (just the most relevant)
#include <list>
#include <string>
using namespace std;
[Code] ....
Of course, when the player saves the game, the inventory has to be saved too.
game.cpp(just the m. R.)
#include <fstream>
using namespace std;
class CGame{
[Code] .....
Now, in my code I write the linked list into the file savegames.sav
void CGame::save(CPlayer* player){
m_out.open("savegames.sav", ios::out);
m_out.write((char* ) &player->m_inventory, sizeof(player->m_inventory));
m_out.close();
}
In another function i load the list:
void CGame::load(CPlayer* player){
m_in.open("savegames.sav", ios::in);
m_in.read((char* ) player->m_inventory, sizeof(player->m_inventory));
m_in.read();
}
And when i access the loaded linked list with the .empty() function or so, Windows says the following:
<Mygame.exe> funktioniert nicht mehr (in English: doesnt run anymore).
I tried so much to fix that but i dint reach my aim.
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