im learning c++ using visual studio as ide. I'm currently doing io streams, but when i try to open a file, the program doesn't open the file.
here is the code -
#include <iostream>
#include <string>
#include <iomanip>
#include <fstream>
#include <vector>
int main()
{
std::ifstream file;
file.open("Text.txt");
if (file.is_open())
{
std::cout << "open" << std::endl;
}
else
std::cout << "not open" << std::endl;
}
i get the output as not open.
any help is appreciated, thanks
you need to keep the file in the directory where the executable is generated by default when using Visual Studio. this is typically located in your solution directory under a folder called Debug/Release depending on your configuration. check the project settings to see where the executable will be generated and copy the file there.
I had a similar problem opening the csv file from cpp file and I found a solution by placing my csv file in the same folder where my source files and especially the cpp file(from which I am trying to open it) is placed.
1)Make sure the path you given is correct.
2)Make sure the file you trying to open is already using by other processes.
Make sure the file exists the path given and and try by giving the full path of the file , if it works ,then make your adjustments.
Try to open the file manually and check if their is any problem with the file.
Check your file is protected by read-only or something like that.
Try to work with the below sample code, and reply me what error you are getting.
file reading sample
file writing sample
Related
Hello I am currently following a book on c++ and currently learning on file i/o
I am trying to open a .txt file and the result is everytime "could not open file
#include <iostream>
#include <filesystem>
using namespace std;
int main(int argc, char* argv[])
{
ifstream file_reader("myfile.txt");
if (!file_reader.is_open()) {
cout << "could not open file" << "\n";
}
int number;
file_reader >> number;
return 0;
}
I'v tried to put the .txt file into debug folder and project folder but no success.
By default, Visual Studio C++ projects execute with the directory containing the .vcxproj file as the working directory (where all file operations are relative to).
You can see this if you right click your project in the "Solution Explorer" -> "Properties" menu item. The on the left of the new window select "Debugging". On the right the "Working Directory" item is most likely set to "$(ProjectDir)".
project folder but no success.
So assuming you didn't change that setting, this should definitely work. Make sure you did place the file there, and that it is properly named (if using Explorer, be sure to have "File name extensions" enabled under "View", so you don't end up making like a myfile.txt.txt by mistake).
It is also possible opening the file fails for some other reason (unfortunately C++ error reporting on this is extremely limited). For example if the file permissions do not allow your program to read it.
If still no luck, you could maybe try writing a file, and see where it puts it.
ofstream file_writer("lostfile.txt");
While following along the vulkan-tutorial I've encountered a problem. I am simply unable to open files using the method he uses.
I have a file called shader.frag.spv, which is fragment shader compiled to spir-v code. It is in my source folder, where my readFile is as well.
Here is the code that reproduces my problem:
#include <iostream>
#include <fstream>
void readFile(const std::string& filename) {
std::ifstream file(filename, std::ios::ate | std::ios::binary);
if (file.is_open())
std::cout << "test";
else
{
std::cin.get(); // I always land on the else block
}
}
int main()
{
readFile("shader.frag.spv");
}
Restarting visual studio, changing the name of the file, altering its content, moving it to separate folder, using an absolute path. None of this has solved my issue.
Any ideas?
The code should work, given that the file is in your current working directory already, check that!
By default current directory in Visual Studio, is the project root, not where the executable file is, as #someProgrammerDude mentioned.
If you are not sure about it, check C++ Visual Studio Current Working Directory.
I'm trying to open a text file in c++ with ifstream but it won't locate the file even though the file is in the same directory as the .cpp file:
#include <fstream>
std::ifstream textInput("words.txt");
if (!textInput) {
return false;
I've triple checked and the file definately exists and is named correctly. I'm not sure if I'm doing something wrong with ifstream or with the path.
EDIT: I put the file in the current working directory of visual studio, it shows the files relative path as "words.txt", but it still can't find the file.
Find out where you application is running (what is know as the "current working directory") using:
TCHAR NPath[MAX_PATH];
GetCurrentDirectory(MAX_PATH, NPath);
std::cout << NPath << std::endl;
Or if you are using C++17, you can do it using the standard library:
std::cout << std::filesystem::current_path().string() << std::endl;
Make sure that the file is located in the same path as the above snippets print.
Does anyone know why the file isn't opening? I also tried just putting "infile.txt" and placing it in the folder of the program and also the debug folder but the ways I used to check for open error both triggered meaning that it could not open. I know I can hard code the location but I don't want to.
I heard you should do stringobj.c_str() but I don't know if that's accurate?
#include "stdafx.h"
#include <iostream>
#include <string>
#include <fstream>
using namespace std;
int main()
{
ifstream infile;
ofstream outfile;
string fileloc = "infile.txt";
infile.open(fileloc);
if (!infile)
{
cout << "open fail 1" << endl;
}
bool fail = infile.fail();
if (fail)
{
cout << "open fail 2";
}
return 0;
}
Note that the directory structure (at least for VS2013) is
<base>
- Solution Directory
- Debug
- Release
- Project Directory
- Debug
- Release
The program by default runs in the project directory (even though it is built to the solution/debug directory).
If you accepted the default naming convention when starting your project, you should be putting your file in the "Projects\ConsoleApplication1\ConsoleApplication1" directory, not "Projects\ConsoleApplication1"
Check your working directory in Project Settings -> Debugging. Make your file available there.
First, the documentation for the signature of
std::ifstream::open( const char * filename, ios_base::openmode mode=ios_base::in)
does indicate it requires a const char *, exactly what std::string::c_str() provides. However, there is an overload for open which accepts a const str &, which means it works the same way for both on most implementations.
Otherwise, what you're grappling with is known as the current working directory (or cwd). Apparently you're not sure where THAT directory is. It may be different while you run the debugger on Visual Studio than it is when you run your program from the command line, and it may be different in various IDE's.
I'm not sure why you want to ensure your program only opens a file by name in the current directory, and not give the full path, but...
You may want to inquire what the current working directory is, so you can solve the mystery wherever you try this. In my Visual Studio 2015, the directory ends up being the directory ABOVE debug, but that depends entirely on how your project is configured, and we can't see that out here.
So, try:
std::string cwd = getcwd( NULL, 0 );
This requires a header <direct.h> on Windows in Visual Studio, but it will give you the directory you're trying to figure out.
with
string fileloc = "infile.txt";
if you put infile.txt in the same folder of the cpp file, it should be fine.
btw I delete your first line
#include "stdafx.h"
I use cygwin console, may have minor diff
For my issue - i was stuck at loading image by opencv - i was wrong to place directory with jpg in the root of the C++ project
WRONG:
CORRECT:
Hi I am currently using CodeBlocks 13.12 on OSX.
I am trying to open the following .txt file
line 1
line 2
line 3
My code is just:
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
int main()
{
cout<<'\n';
std::string line;
ifstream myfile("textex.txt");
if(myfile.is_open())
cout << "File is open";
else
cout << "File not open";
cout<<'\n';
return 0;
}
I have also included the file in the project folder and have tried linking it and compiling it.
When I run the code, it displays"File not open" and I'm not sure why?
I'm new to c++, can someone please explain why this isn't working?
Possibly because the project folder is not set as the working directory. Try specifying the full path.
Instead of
ifstream myfile("textex.txt");
Try
ifstream myfile;
myfile.open("/Users/name/Code/textex.txt"); // Use the full path
Try typing the full path of the file instead of just the file name.
Tell me what happens then.
On another note but unrelated, since you are using the "using namespace" directive, you may as well omit std:: from string just like you did with cin and cout. It is not a big deal, just the look of the code.
When you run your program from Code::Blocks it runs on project folder so your text file must be in your project folder, otherwise text file must be in the folder where your executable is.