Why file isn't opening C++?

Question

I am trying this code for a few first times only. I am not able to get to the root of the error.

Here is the code:

#include "stdafx.h"
#include <iostream>
#include <fstream>

using namespace std;

int _tmain(int argc, _TCHAR* argv[])
{
    fstream file;
    file.open("C:\\Users\\AfzaalAhmad\\Documents\\text.txt");
    return 0;
}

The file is present at the location. Here is a screenshot of the file system.

There is no exception in this case, but the file is never opened!

Where am I missing code?

Do you need the double back-slashes? Shouldn't it be something like C:\path\to\my\file ? — sergico, Feb 01 '14 at 15:19
@sergico I need to escape the backslash .. since when I use single slash it gives error! — Afzaal Ahmad Zeeshan, Feb 01 '14 at 15:20
The double backslashes are necessary, the first makes the second literal — chrisb2244, Feb 01 '14 at 15:20
Try forward slashes? Supposedly windows compilers will recognise either in full file paths. By the way, I assume you're running some test to check that it's not open? — chrisb2244, Feb 01 '14 at 15:21
How do you *know* the file doesn't open? You don't check for it? — Some programmer dude, Feb 01 '14 at 15:21
No I don't, I just check whether there is a new file opened or not. isn't that the way ?? — Afzaal Ahmad Zeeshan, Feb 01 '14 at 15:22
It doesn't open in notepad or something you know - you just have a fstream object inside the C++ program that lets you read it from there. For example, ou can then say `std::string line; while (getline(file, line)) std::cout << line << '';` to write the file content to the stdout (terminal) (you'd need to `#include ` and `#include ` for that too. — Tony Delroy, Feb 01 '14 at 15:23
@AfzaalAhmadZeeshan: Out of interest, what did you think would happen? And which book are you using? — Lightness Races in Orbit, Feb 01 '14 at 15:28
No book, this site: tutorialspoint.com/cplusplus I thought I could open a file like double clicking on it! I misunderstood...@LightnessRacesinOrbit — Afzaal Ahmad Zeeshan, Feb 01 '14 at 15:30
@AfzaalAhmadZeeshan: Yeah, you should definitely learn from a book, not "tuts" on the internet. — Lightness Races in Orbit, Feb 01 '14 at 15:51

score 5 · Accepted Answer · answered Feb 01 '14 at 15:23

5

The command you've written will open a handle to a file at that location. In order to do anything with it, you'll need some sort of read or write operation. Probably your code is working fine :)

For example, following your file.open("...") line:

file << "This is some text to send to my now open file\n";
...
file.close();

answered Feb 01 '14 at 15:23

chrisb2244

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You're welcome. I edited my answer with some examples - the other answer from @karakale is likely to be helpful for you there :) – chrisb2244 Feb 01 '14 at 15:25
I would have tried out his tutorial link, but I don't know why that site is down since 3 days here: http://imgur.com/RveTZfP .. – Afzaal Ahmad Zeeshan Feb 01 '14 at 15:28
1

@AfzaalAhmadZeeshan: No, you should use [a good book](http://stackoverflow.com/questions/388242/the-definitive-c-book-guide-and-list). – Lightness Races in Orbit Feb 01 '14 at 15:30
Well, I confess to having used cplusplus.com quite a bit, but I'm told it's not very good. As @LightnessRacesinOrbit points out, SO has a question about the best C/C++ books with some pretty extensive answers. – chrisb2244 Feb 01 '14 at 15:48
@chrisb2244: The reference, nowadays, is fairly accurate and well maintained, but the forum contributions are not inherently peer reviewed, and because of the name of the site you get a _lot_ of entry-level contributions that will teach you bad practices and bugs, written by those who don't yet know any better. It's a vicious cycle, really. The tutorial is _okay_, but no substitute for a full book written by a prestigious author. – Lightness Races in Orbit Feb 01 '14 at 15:50

Why file isn't opening C++?

1 Answers1