I am having a bit of trouble running my C++ program as a .exe file. It takes in one input file (specified in project properties > debugger: < input.txt) and outputs two files.
When I run the program within Visual Studio itself, everything completes just fine. The files being written are correct. However, when I try to run the .exe file, it does not seem to do anything.
Project name = test
I am running the .exe from: test\Debug\test.exe. That's the only location within the VS project folder that I see an .exe file. I have also moved the expected input.txt to this same location. Can anyone help me troubleshoot?
It sounds like you are passing input.txt as an argument to the program. In this case you have to start the program like this:
test.exe < input.txt
That's what VS does for you when you debug the program. Putting the file next to the program is not the same as passing an argument.
Related
I have inherited a project to work on and the initial build was developed on linux. I dont know if this matters or not but thought I would share it.
In order to debug the project on a windows machine I first use the CMakeGUI on win7 to create a Visual Studio Solutions file to open the project using Visual Studio 2013 and then set the startup project and build the project I am interested in. Up till now everything is okay. Now comes the confusing part.
On load the program is suppose to read a file lets call it in.dat and is declared in const char * inputFileName this variable is then passed through a class which attempts to open then file to obtain data.
fstream fs;
fs.open(inputFileName.c_str(), fstream::in);
if(!fs.is_open())
{
std::cout << "Cannot open input file!" << std::endl;
exit(0);
}
This where I am stumped...the file when placed in the debug folder for some reason cannot be opened i.e fs.is_open() returns false when I try debugging the application BUT if I cd directly into the debug folder of the project, outside of VS, and run the executable it runs as expected i.e fs.is_open() now returns true.
Your debugger's working directory defaults to your project's root directory and the binary is in the \debug subdirectory, resulting, in effect, to the path to the input file being wrong.
Set the debugger's working directory to \debug.
Here is more info on that:
https://msdn.microsoft.com/en-us/library/kcw4dzyf(v=vs.120).aspx
The IDE I'm using is VS2010 for writing C++
I want to execute the command cmd C:\utilities\unix\tail.exe -f -n15 $(ProjectDir)Log.txt every time the program I'm coding is run from within the IDE. (This command should open a console to track changes made to the file Log.txt)
There are ways to make a command run every time the program is built, but I can't find a way to make a command run whenever the program itself is run, even if it's already built. Where or how might I be able to set that kind of thing up?
I've tried putting $(TargetPath) & C:\utilities\unix\tail.exe -f -n15 $(ProjectDir)Log.txt into the project's Properties->Debugging->Command (TargetPath is the full name of the debug executable) but VS reads the entire thing as a filename and gets confused.
You can create a file run.cmd for example next to the vcxproj file, which would contain:
%1
C:\utilities\unix\tail.exe -f -n15 %2Log.txt
And then in Properties->Debugging->Command you write:
$(ProjectDir)\run.cmd
and in Command Arguments you write:
"$(TargetPath)" "$(ProjectDir)"
I may have misspelled the macros, but you get the idea: it executes first your program and then whatever you want.
Edit: Unfortunately it works only if you start without debugging (Ctrl+F5), because otherwise the debugger tries to attach to run.cmd and complains that the format is unsupported.
I've been using windows in a class I've been taking but I am trying to run a basic code to figure out how to open/close/input/output from files on Xcode and the code I usually use on visual studios isn't working any idea why? thanks!
#include <string>
#include <iostream>
#include <fstream>
using namespace std;
int main()
{
ifstream fin;
ofstream fout;
string input;
fin.open("inputFile.txt");
if(fin.fail())
cout << "File failed to open." << endl;
fin >> input;
fout.open("outputFile.txt");
fout << input;
}
Put your .txt files in the same directory where your main.cpp file is (or anywhere you like).
In Xcode go to Product > Scheme > Edit Scheme > Run (on the left) > Options (middle top)
Down under Options for "Working Directory" check “Use custom working directory” and set it to the directory where you .txt files are located.
To work with the files, you will have to specify just file names, e.g. in_file.open("inputFile.txt"); no path is necessary.
Here's a completely different approach: Have Xcode copy the input file for you.
Select your project in Xcode
Select Build Phases
Click the '+' button to create a new Build Phase
Select New Copy Files Build Phase
Select Products Directory
Click the '+' button to add your file
Click Add Other
Select your input file and click Open
Check the Copy items… checkbox and click Finish
Now every time you build your project, the input file will be copied to the same folder as the executable no matter where it is built. Of course, to see the output file, you'll still need to find the executable in Finder.
The answers don't really explain the problem so I thought I'd do that.
When you pass a relative path like "inputFile.txt" to file APIs, it's treated as relative to the working directory when the program is executed. This is the same as the 'working directory' when you use cmd.exe or Terminal.app or command lines in general. The Unix command pwd ("print working directory") displays the current working directory. On Windows running the command cd with no arguments performs the same function. (On Unix running cd with no arguments will change the working directory to the user's home directory.)
When you run a program from the command line, the command line shell sets the program's working directory. When you run a program from within an IDE, the IDE sets the working directory. Since, unlike on a command line, there's no obvious answer for what the IDE should set as the working directory, Visual Studio and Xcode set the working directory to different locations by default: Visual Studio sets the working directory to $(ProjectDir), the directory containing the Visual Studio project file; Xcode sets the working directory to the build products directory, i.e. the location the executable was written to.
Some possible solutions to your problem are:
Do not use a relative path, and therefore don't depend on the working directory. This isn't much help in making the program more portable, because the absolute paths will also differ between platforms, and so you will still have to 'configure' the program for each platform. In fact using an absolute path is worse, because it means your source code must differ, whereas it would be better to keep that difference confined to each platform's build configuration.
Configure the IDE to use your desired working directory. Visual Studio can be configured by right clicking the project, selecting Configuration Properties > Debugging > Working Directory, and setting the working directory to the desired path (potentially using Visual Studio build variables).
nepete's answer describes how to configure the working directly set by Xcode.
Configure the IDE's build process to copy your data files to an appropriate location. In Visual Studio you would do this in a C++ project by configuring the project's Properties > Configuration Properties > Build Events.
SSteve's answer covers how to configure additional build steps in Xcode.
I'm guessing you have inputFile.txt in the folder that contains your source code. That's not going to work. You need to put it in the folder that contains the generated executable. To find that folder, right-click on your app under Products and select Show In Finder.
This image shows what it looks like for a command line program. It also shows the Finder window that was opened. As you can see, it is a different folder than the one containing the source code.
As suggested by nepete, edit the scheme, but use $PROJECT_DIR as the custom working directory. Helps with moving the project around, or working in two different environments (e.g., home and office).
BTW. $PROJECT_DIR is one of the Xcode Environment Variables, and also helps with passing file names as command line arguments to programs (settable under "Arguments" in the scheme).
I've struggled with the same problem today. I wanted to add C code to my Swift project and my file pointer was always NULL.
Unfortunately, in XCode 9 for iOS app, I couldn't change the working directory. Changing Build phases didn't help me either. After 4+ hours of trial and error, that's what I've come up with finally and it works:
when copying files to XCode, I've chosen "Create groups", but I needed to choose "Create folder references":
I created a new objective-c file (.m) and copied all my C code there.
I left untouched .h files (XCode generated bridging header and my own .h file with public functions declaration). Now my project structure looked like this:
In my dict.m file in place of previous plain c fopen part:
FILE *dic = fopen("dictionary.txt", "r");
I added obj-C code:
NSString *filePath = [[NSBundle mainBundle] pathForResource:#"dictionary" ofType:#"txt"];
FILE *dic = fopen([filePath cStringUsingEncoding: NSUTF8StringEncoding], "r");
And it works now without any problem! It's just amazing!
ps I decided to write this answer in case it will help someone like me and will save them some time. If you know how to change working directory in XCode 9 for iOS, please, leave me a comment - now I am really curious why I can't find it.
I am new to c++ and am making a very simple program. All my program does is call a function from the main function, which reads in a text file and returns. To check that I am reading in the file correctly, I am trying to print out the strings I have read in. The print out (cout) works properly when I run from Visual Studio (f5). However, when I run the executable from command line, none of the print outs from my function show up. Only print outs directly in the main function appear. I cannot find a similar question elsewhere. Any help would be appreciated.
When you run a program from within VC++ the current directory is set to the project directory by default, but the application is by default in a different folder.
E.g. the application may be:
D:\Work\MyApp\Debug\MyApp.exe
But the project directory may be:
D:\Work\MyApp\MyApp\
When you start the program from outside of VC++ you need to take steps to make sure the current directory is correct, or that the executable and any data files it refers to are in the same folder.
The default working directory for an IDE-launched project in Visual Studio is the project folder. This is the folder where you project file resides (the .vcproj or .vcprojx file is the project file).
If the data file you are reading is in the same folder, code like this:
std::ifstream inf("datafile.txt");
will succeed because the current working folder and the folder where the data file resides are the same.
However, if you switch to where the executable was written (typically this is the project-dir/Debug or project-dir/Release folders) and run the same executable from a command-shell, the data file will not be found.
To test this is the case. Do the following:
Open a command prompt.
Switch to the project folder where your data file resides.
Run the executable with a specified path: ./Debug/YourProgram.exe, for example.
Note: you can avoid this by having the program take the data file name as an argv[] parameter. Then your program will simply use whatever file you tell it to at launch-time.
I have program in C++ that runs great but it has different steps in it. It opens a file first then does some calculations based on the data it gets from the file. Now I'm trying to run it through matlab. I tried mex but it got too complicated because I have VS 2010 Express and MATLAB 2007b. And so mex can never find my c compiler.
I'm now trying to just run it straight from the C++ program executable file. Here's how I tried to do it:
system('C:\path\file.exe')
it would run but the command window freezes and I have to close Matlab every time to get back on track. Then I tried to double click on the executable file it self. It flashes but I can see it outputs something from my file "file could not be uploaded" which is generated by a part of my program if it cant find the file.
So then I realized it's probably because of that that caused it to not run and crash.
So I wrote a sample code to open the file first before the system command open the .exe file. I've done something like fopen('fname','r'), but nothing works. Please note that this file I'm trying to open is a .COF file.
I tried running the .exe file using debug and release modes but nothing happens. It gives no errors which means it sees the .exe file but the command line doesn't come up and matland command window freezes.
After running, it's supposed to prompt the user at the command line then take input arguments and output something...
Please help....
I am guessing that your .COF file is in a different path than what's accessible by your binary. If you can recompile, try an absolute path name, and test it first without MATLAB.
There are more thorough ways to solve this, like passing the filename to your binary as a command line argument, or to read up what the rules are for the "current directory" when you use system, but perhaps you'd be happy with the quick solution.