This is happening in both Visual Studio and XCode
#include <fstream>
#include <iostream>
using namespace std;
int main() {
ifstream input;
input.open ("matrices.txt");
if (!input.is_open()) {
cout << "not open!";
} else {
cout << "open!";
}
input.close();
return 0;
}
My file is not opening. The text file matrices.txt is in the same directory.
What is "same directory" in this context?
For a file to open like this, it has to be in the working directory of the executable when run in the debugger.
For Xcode; this means adding the files to the Copy Files build phase (accessible by editing the executable's target); and adding it to the Products Directory, selected from the dropdown.
In Xcode if you want to work with a file you have to put it in a folder called DeriverData. You can navigate to it by doing the following:
Xcode > preferences > click on Locations.
this brings up the following window
you can click on the small arrow to the right of the path: /Users/dulybon1/Library/Developer/Xcode/DerivedData
It will open the directory containing a list of all your Xcode projects. Find your project and navigate to: build > products > debug
as seen below:
Then you can put your files there. "a1.txt" and "a2.txt" are files that I have put there to work with. And I think the file needs to exist before it can be opened, so just create blank files if you are planning of using them. Hope that helps
Related
#include <iostream>
#include <fstream>
using namespace std;
int main()
{
ifstream file;
file.open("./cp.txt");
if(file.good())
{
cout << "done!";
}
else
{
cout << "fail";
}
return 0;
}
why does my code can't cp.txt file? it is in project folder. i'm using gnu/linux.
as open i mean the program will open it in some text editor i.e:. leafpad
as open i mean the program will open it in some text editor i.e:. leafpad
That's not going to happen.
When you open an ifstream object it means the file is open for reading by that object, it does not mean a text editor is launched and displays the file!
Maybe what you want is:
system("leafpad cp.txt");
The system function runs another command, in this case it runs the command to launch leafpad with your file as an argument.
Note that the file will be searched for in the current working directory of your program, which is not the same as your "project directory". If you don't know what the current working directory is when your program gets run then you will need to provide an absolute path to the file, not a relative path like cp.txt
you have mentioned having a project folder. if you use an IDE,
it might change the current directory of the running executable.
try deleting the file and creating the file within your code eg:
ofstream ofile;
ofile.open("./cp.txt");
ofile.close();
if you get an output done! then search for the file.
I am running a program using this simple example code to output a text file. I am using Xcode and simply started a new C++ project from command line tools. For some reason the program does not output any file onto my Mac. Please help figure out why XCode will not output any file to my computer? Thanks!
#include <iostream>
#include <fstream>
using namespace std;
int main() {
double myNumber = 42.5;
fstream outfile("test.txt", fstream::out);
outfile << "The answer is almost " << myNumber << endl;
outfile.close();
}
Dang I can't believe I figured it out, it was an option in Xcode. So I clicked on the bar at the top of xcode near the stop button with the text (Project Name > My Mac 64-bit)
Then clicked edit scheme. The clicked on the options tab and clicked use custom working directory. Then selected a working directory. Now the text file appears!
As mentioned above, editing the scheme worked for me but getting to the scheme was different.
Use the Product Menu
Select the Scheme option
Select the Edit Scheme option
Click the Options Tab
Tick the "Working Directory" item
Click the small icon at the right end of the text box.
Select the directory
I also had the Run/Debug option selected in the left hand pane of the window.
To find the current working directory, in the project navigator, under the "Products" folder, right-click the product and choose "Show in Finder". In this directory you will also find the compiled code.
For example:
~/Library/Developer/Xcode/DerivedData/<project name>-gweghgfqkjkidjfhcgetdryechjz/Build/Products/Debug
I have created a text file with content. It is located in the same folder as the cpp files. And I have confirmed several times that the file exists. When I run g++, compile and run it finds the file. When I run it in Xcode, it does not work. If fails to find the file.
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
int main () {
string line;
ifstream myfile ("example.txt");
if (myfile.is_open())
{
while ( myfile.good() )
{
getline (myfile,line);
cout << line << endl;
}
myfile.close();
}
else cout << "Unable to open file";
return 0;
}
Your file fails to open because XCode launches from the IDE in the default build location, which is actually a temporary directory off somewhere on your disk. If you want change the working directory at launch-time to something else (like the location where your files can be found):
Select the Product/Edit Scheme... menu option.
Select the Run schema in the left list.
At the bottom Options tab on the right pane should be a "Working Directory" option. Check the checkbox and set the custom working directory to someplace you know (your "/Users/yourname" home directory is a decent place that I use).
Make sure any "current directory" data files you need for your program execution from the IDE are in this directory.
And in case you didn't see it, this is also the place where you can configure command-line arguments (on another tab) of the same dialog.
Try to add files to the project in XCode or use the absolute path instead.
This is supposed to create a file in my project directory called "tuna.txt". When I run it, it compiles successfully, however no file is created. I am on a mac using xcode. I have searched my computer for other places where it might have been created, but it seems as if the file was not created at all. Any ideas as to why it doesn't work?
#include <iostream>
#include <fstream>
using namespace std;
int main(void){
ofstream file;
file.open("tuna.txt");
file << "I love tuna and tuna loves me!\n";
file.close();
return 0;
}
I assure you that barring errors (which you're not checking for) a file is created. Xcode has a tendency to use the final build-dir as the current working directory when running from the IDE. you can change this by editing the active Scheme.
Click on the Project box to the right of the STOP button on the main toolbar
Select Edit Scheme
Select the "Run" sub scheme in the left pane list.
Select the Options tab,
Check the "Use Custom Working Directory" checkbox
Set the working directory to some place you know (like your project root folder).
Note: This is also where you will setup any command line arguments (those are on the Arguments tab, not the Options tab), should you desire to do so.
In the Products folder (in the Project Navigator of the Navigator tab on the left-hand side of the Xcode IDE) you will find the executable. Click on the executable.
If not already shown, make sure the Utilities tab on the right hand-side of the Xcode IDE is shown and the Show the file inspector is selected.
From the inspector, you will see Full Path showing the path to the executable, and at the end of it, there will be an arrow. Clicking on this arrow will open up the Finder window to that location, and this is where you should also see all the text files and other files that have been created from within the program.
PS. The reason that you couldn't find the tuna.txt file when using the search is because it is in a hidden folder along with the executable.
First of all you must check whether file has been opened/created or not. Then you should search for the file. Most probably the file hasn't been created yet. Here is the code:
#include <iostream>
#include <fstream>
using namespace std;
int main(void){
ofstream file;
file.open("tuna.txt");
if(file.is_open())
{
file << "I love tuna and tuna loves me!\n";
file.close();
}
else
cout<< "No file has been created!\n";
return 0;
}
As you haven't given an absolute path to open function.See the folder where your code file is. Most probably the file will be there.
Ok, so this is the first time I've coded C++ in Xcode (I'm used to ObjC)and I've now started a programming course at my college.
I'm trying to open a file (either hard coded or from user input in the console) and no matter what I try, it says the file won't open (through error checking)
I'm assuming it's because the test.txt file I have isn't in the assumed root directory, so if that's the case, what is the root directory?
Here's my code so far:
//include files
#include <iostream>
#include <stdio.h>
#include <fstream>
using namespace std;
//Global Variables
short inputPicture[512][512];
short outputPicture[512][512];
//Function Prototypes
void getInput(char* in, char* out);
void initializeArray(ifstream* input);
//Main
int main(){
//local variables
char inputFile[32];
char outputFile[32];
ifstream input;
ofstream output;
getInput(inputFile, outputFile);
cout << inputFile << endl;//test what was sent back from the function
input.open(inputFile, ifstream::in);
if (!input.is_open()){//check to see if the file exists
cout << "File not found!\n";
return 1;//if not found, end program
}
initializeArray(&input);
return 0;
}//end Main
//Gets initial input from user
void getInput(char* in, char* out){
cout << "Please designate input file: ";
cin >> in;
cout << "\nPlease designate an output file: ";
cin >> out;
}//end getInput
//Sets the global array to the information on the input file
void initializeArray(ifstream* input){
}//end initializeArray
Please let me know if there's something else wrong I'm doing, as I'm sure that's always a great possibility :)
The default directory should be relative the application's working directory, which is usually the same place the application is located (debuggers can mess with that, sometimes).
For simple testing, just specify an absolute path in the command line (or code).
To get the current directory (to see), the getcwd() C function (also usable in C++) will help. Something like:
char * dir = getcwd(NULL, 0); // Platform-dependent, see reference link below
printf("Current dir: %s", dir);
That should display it in the console. The getcwd function has a few variations depending on what you run on, I've not tested on Mac, but info here:
http://linux.die.net/man/3/getcwd
In the Xcode (v7.1.1 at the time of writing) sidebar, there's an automatically generated folder called "Products". Inside you'll find the executable of your project (assuming you've built your project at least once). Right-click it & choose "Show in Finder". A folder will open in Finder. That's the working directory of your program, & you'll notice it's not actually inside your project's folder.
You can have Xcode use a different directory instead. In the top toolbar, on the left side where it shows your project name next to the active build architecture, click on the Project name > Edit Scheme…
Then look for an option called "Working Directory" in the sheet that appears. Tick the checkbox & then choose a custom directory. Note: Make sure the "Run" option is the selected one in that sheet's sidebar.
The "root" directory that your executable is looking for the file in is not the actual / root directory of the file-system, but is the directory that the executable is executing in ... if you are using Xcode, this may be buried inside one of the build directories automatically created by Xcode for your project rather than a user home folder or home folder sub-directory like /Users/XXXXXX/Documents.
The "default directory" is the directory from which the executable was executed. Usually this is in the same folder as the executable, although if you do stuff like dragging and dropping files on an exe, it can change the startup path.
The path can also change if you're running the program from inside your IDE. The IDE starts the executable, so there's no telling where it's doing it from. You'll have to find where it stores executables and put the file in there, or use an absolute path.
In my case,
- getcwd(NULL, 0) returned "/".
- and couldn't use abusolute path.(It changes on each terminal deployed.)
So I got the path by ObjC code and throw it to c++ function.
1.Put files in top directory of xcode project. And check they are included in "Targets"->"Build Phases"->"Copy Bundle Resources".
2.Get the path by ObjC code.
NSBundle* bundle = [NSBundle mainBundle];
NSString* resourceDirectoryPath = [bundle bundlePath];
NSString* path = [resourceDirectoryPath stringByAppendingString: #"/"];
3.And throw it to c++ function.
[self cppFunc:[path UTF8String]];
4.Then you can make an ablsolute file path in c++.
std::string file = path(arg) + "filename";
It worked for me.