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");
Related
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
I'm learning C++ as first programming language and I can't figure out how to run Hello World program. I was googling for solution but I did not find any.
#include <iostream>
using namespace std;
int main() {
cout << "Hello, World!";
return 0;
}
Unable to start program
'C:\Users/thom/Desktop/C++/Visual/firstproject/Debug/Hello World.exe'.
The system cannot find the file specified.
If you create a .cpp file in File > New > File > C++ File?
If so, the path is not included in the project directory, causing the compiler to fail to find the file.
The correct way is to create a cpp file in the project directory under Explorer.As shown below：
You can modify the name of the .cpp, and don't modify the default location.
Now you can try to build and run the executable.
Try Build -> Rebuild Solution, find the executable in the path shown at the output to run it.
You can also try pressing Ctrl+F5 to build and run
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:
I keep getting this error with these lines of code:
include <iostream>
int main()
{
cout << "Hello World" >>;
system("pause");
return 0;
}
"The system cannot find the file specified"
The system cannot find the file specified usually means the build failed (which it will for your code as you're missing a # infront of include, you have a stray >> at the end of your cout line and you need std:: infront of cout) but you have the 'run anyway' option checked which means it runs an executable that doesn't exist. Hit F7 to just do a build and make sure it says '0 errors' before you try running it.
Code which builds and runs:
#include <iostream>
int main()
{
std::cout << "Hello World";
system("pause");
return 0;
}
The code should be :
#include <iostream>
using namespace std;
int main() {
cout << "Hello World";
return 0;
}
Or maybe :
#include <iostream>
int main() {
std::cout << "Hello World";
return 0;
}
Just a quick note: I have deleted the system command, because I heard it's not a good practice to use it. (but of course, you can add it for this kind of program)
I had a same problem and this fixed it:
You should add:
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.1A\Lib\x64 for 64 bit system
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.1A\Lib for 32 bit system
in Property Manager>Linker>General>Additional Library Directories
Another take on this that hasn't been mentioned here is that, when in debug, the project may build, but it won't run, giving the error message displayed in the question.
If this is the case, another option to look at is the output file versus the target file. These should match.
A quick way to check the output file is to go to the project's property pages, then go to Configuration Properties -> Linker -> General (In VS 2013 - exact path may vary depending on IDE version).
There is an "Output File" setting. If it is not $(OutDir)$(TargetName)$(TargetExt), then you may run into issues.
This is also discussed in more detail here.
This is because you have not compiled it. Click 'Project > compile'. Then, either click 'start debugging', or 'start without debugging'.
I resolved this issue after deleting folder where I was trying to add the file in Visual Studio. Deleted folder from window explorer also. After doing all this, successfully able to add folder and file.
I was getting the error because of two things.
I opened an empty project
I didn't add #include "stdafx.h"
It ran successfully on the win 32 console.