Why can't I read a file with Code::Blocks C++? - c++

I've created a file in Code::Blocks called datos.csv, and I have this code:
std::ifstream file("datos.csv");
if (file) {
cout << "Managed to read file successfully.";
}else{
cout << "Unable to read file.";
}
But it is unable to read the file.
I tested the same code with TextMate, which can run C++ files, and it was indeed able to read the file, so I suppose there's something up with Code::Blocks. What am I missing?
My file appears listed in "Others" in Code::Blocks' navigator.

you need to modify the Target Properties, go to Project -> Properties -> Build targets and change the "Executing Working Dir" for the debug/release folder of your proyect, I hope this help.
Greetings.
Saludos.

It can't find the file to open it. Since you are not using absolute paths to open the file it must be relative to the current working directory. If you are launching from the debugger you can set the working directory used when the application is launched. Make sure that directory is the same as where the csv file is located.

Related

ifstream will not open

The file exists in the directory, and I've tried running Visual Studios in Administrator Mode. However, ifstream can not find the file I give to it.
Here is the code I am using:
std::ifstream instream;
instream.open("appdata.txt");
if (!instream)
{
std::cout << "Could not find appdata.txt!";
}
But I am always greeted with Could not find appdata.txt! when I run the program.
Here is a picture of my directory, for proof that I have it spelled correctly and it exists.
So, my question is, am I missing something so glaringly obvious that I am glazing over it each time I look? I can not figure out for the life of me why instream can not open appdata.txt.
This is a problem with current directory being set to something else than a dir where your file is (usually your home folder if executing from explorer).
Try executing the program from command line from directory where your file is.
EDIT
If you want to set the working directory to some specific location, check this: https://msdn.microsoft.com/en-us/library/aa363806.aspx
Add the file by right clicking on project name on visual studio interface.
This will keep your file in the right directory.
If you want to add in the directory by yourself, first add a file using the method I said above and the find which is the folder you should keep so that you can use that file by mentioning just the file-name. And then you can add your files in that folder.

I am having trouble opening a .txt file in my C++ program

I have put it under the Source Files folder. I have set my working directory to $(SolutionDir)$(Configuration)\ (im not sure if that is right, i saw it somewhere) could someone help me troubleshoot.
int main()
{
cout << "program running" <<endl;
pair<int, unsigned int> mypair;
ifstream myfile;
myfile.open("numbers.txt", ios::in);
if (!myfile.is_open()){
cerr << "can't open input file" << endl;
}
else
{
cout << "file opened" << endl;
}
getchar();
myfile.close();
}
...output is: can't open input file
To figure out what directory you're pointing to, try to create a new file instead of opening one:
std::ofstream("out_test.txt");
Then you can find that file searching with File Explorer into the solution dir.
There is such thing as current directory for an application. When you run an app from VS working directory would be current one.
If you specify file name with relative path (or no path at all) OS will try to find that file relative to that directory. Where executable file and especially source file(s) are located completely irrelevant. So solution could be either set working directory to where numbers.txt is located (or move nubers.txt there), or use relative path something like foobar/numbers.txt or even ../foobar/numbers.txt etc or use absolute path.
okay I managed to figure it out..with help :) I did what Paulo M said :
To figure out what directory you're pointing to, try to create a new file instead of opening one:
std::ofstream("out_test.txt");
Then you can find that file searching with File Explorer into the solution dir.
After I figured out where the file got sent I added a new file w/ some integers to that dir and made sure the working directory was the same.I'm not sure if i had to change it? (can files be sent elsewhere?).
I had tried to do this before but I was not able to move my txt file into this directory by copy paste..so gave up. But anyhow I just right clicked/new text document/ and edited the doc with some numbers. then changed my program to open this new document.
saving file directly to the directory also worked. :) :) :)
but i am curious why I couldn't just paste it there?

ifstream can't find file that is saved in the directory

I'm writing a program that uses <fstream>. The file I need to include is called employee.dat and it's listed in the directory. I put in a cout statement that says:
ifstream inFile ("EMPLOYEE.DAT");
if (! inFile)
{
cout << "!!Error in opening 'EMPLOYEE.DAT"<< endl;
}
The file is in the directory and there shouldn't be any issues opening/finding it. This is my first time using the ifstream class.
If you are running from the Visual Studio environment, be aware that your executable probably isn't in the same directory as your data file. Binaries tend to be built into a Debug or Release folder by default. You have several options:
Move your data file into the correct directory.
Set the Working Directory (in your project settings, under "debugging").
Use a full or relative path for your file name.
It's also possible that you are looking in the right place, but the file is locked. Make sure it's not open in any editor or other program that might prevent other processes from opening it.
Beware that in Visual Studio, the Working Directory (set in the project properties under the Debugging tab) is the location that the exe is apparently located when debugging (and not the actual location of the exe itself)

Can't read file from a C++ program on a Mac

First of all, this is part of my code:
....
string input;
getline(cin, input);
ifstream openFile;
openFile.open(input.c_str(), ios::in);
if(openFile.is_open()){
cout << "File opened" << endl;
}
else {
cout << "Cant open the file " << endl;
}
The result always "Cant open the file". I am very, very sure that the files are exists. I have data1.txt, data2.txt ... data10.txt in the same directory (I used XCode to add new empty file, add the data inside and save it).
I do another test, I create a new directory, copy paste the cpp and data files. I run in terminal, and it works, it can read the data file. Why does xcode cant read my data files? Any idea?
You need to give the full path to the files. Xcode will run the application from the build directory which is not where the code is.
If the files are copied as part of building an OSX or iOS application you should look at the bundle structure to find the directory.
You can tell Xcode to run the executable from the directory containing the data files.
Bring up the info dialog for the target executable, and change the value for 'Set the working directory to:' to either the Project directory or a custom directory'

Open method opens files with full path only C++

File opens if I write the full path (full-path/roots.txt).
File fails to open if I write the filename only (roots.txt)
And yet, roots.txt is in the same folder as the main.cpp.
Is there any settings I should check on XCode?
Here's the code:
string line;
ifstream infile;
infile.clear();
// infile.open("roots.txt");
infile.open("/Users/programming/C++/roots/roots.txt");
if (infile.fail()) cout << "could not open the file: " << strerror(errno);
getline(infile, line);
cout << line;
By default, Xcode working directory is something like ~/Library/Developer/Xcode/DerivedData/project-/Build/Products/Debug. So,if you are trying to use a relative path with respect your project directory or any other, you should manually configure your working directory in Xcode.
You can do this by: Product -> Scheme -> Edit Scheme -> options tab, tick the use custom working directory checkbox and show your path.
If it works when you attempt to open a file with an absolute path and fails with just the filename, your relative path is likely incorrect. Ensure roots.txt is placed in the current working directory. Look into the getcwd function declared in unistd.h.
To change the working directory when you're running from inside XCode: select "Edit Active Executable" in your "Project" menu.
You can adjust your working directory settings at the bottom of the "General" section.
Assuming you're running file from within XCode, the working directory is unlikely to be the same directory where your .cpp file is located. Check what your current working directory is what you think it is. (you should be able to obtain it using a getcwd call)