I have a very simple C++ program with a very simple project setup, but when I run the program I get no output. If I run the program in debug mode, it works perfectly. I am using Eclipse Kepler CDT 32 bit on windows with MinGW. I am somewhat new to eclipse, so it's probably something I did wrong.
The program is:
#include <fstream>
#include <iostream>
#include <string>
using namespace std;
ofstream outfile("testdata.txt");
int main()
{
outfile << "Program Start\n";
cout << "Program Start\n";
return 0;
}
Help!
If the problem is that the program quickly opens and then closes before you can see the output on the screen, then you can just run your program from any shell (CMD on Windows, bash on Linux, etc.). That way, it won't exit once your program ends and you can see the results.
Make sure also that you flush/close your ofstream before your program exits.
The problem is rather not releted to c++ itself. You should check if via "cmd" typying it in "launch menu" after you click start. Find the path of your program, then run it.
For the very beginning it is recommended to spend a few hours with terminal(cmd). To know how things works. After that you will be independent - you will be able to write the code in any IDE. Also simple trick to make it working is to use std::cin.get() . It is prefered to system("pause").
You open the testdata.txt file using the relative path.
And the created file may be created in the project binary output path, where the executable located in.
You can use everything software to check whether a file is created and its created path.
everything
For example, you can type your output file name testdata.txt into everything software to see where output file created.And check if the testdata.txt created in a wrong path or directory.
Related
I am trying to learn C++ now and created a Hello World program. When I compile it on Linux using g++ and it works perfectly fine. When I compile it on Windows using the Build tools, it still compiles the code into machine code, but I can't open the executable. I used the Microsoft build tools as a compiler. The code was:
#include <iostream>
using namespace std;
int main() {
cout << "Hello, World!";
}
The output should be: Hello, World!
**Question already answered:
The program closes because it is not run in cmd. To prevent the program from crashing add
```system("pause");```
at the end**
The executable is showing the correct output on the terminal, but that terminal closes that fast that you don't even realise it.
I'd advise you to open a command prompt, go to the directory where the executable is located and launch it over there. You'll see the desired output.
it possibility because
the app closes immediately after ouputing
add system("pause");
on the end
Its not that you can't open that exe file.
Once you click on that file, it opens up and does its work and closes.
To prevent your exe file from getting closed after doing its operation, you can add following line at the end of the main function :
getchar();
And now once you open your exe file, it wont close automatically, you will need to press "enter" to close it.
#include<iostream>
using namespace std;
int main(){
cout<<"hello world";
getchar();
}
The title is a bit long-winded, but basically, I've written an app that reads and writes its input and output to text files. The entire time, it would read and write the files directly in the same directory as my Xcode derived data->project->build->products->debug folder. This was where everything was being written to and read from. I don't have a custom path set up for the application, so it just saves wherever the app is located. For the first time ever, I ran Apple's Instruments app, to try to learn how to use a profiler. Not long after selecting this app as the target in Instruments, I went back to the Xcode app to run the program some more. Everything works fine in Xcode. It reads from the files and prints to files in the same location as the folder, but if I try to run the actual program itself by clicking on the file and having it open terminal, it no longer reads or prints to the directory that app is in. Instead, its printing and reading from my home folder. I don't know what changed or what caused it to change, but I'm hoping its a simple fix. I'd like for the application to read from files and print files from the directory its located in again. I'm not sure if its an Xcode setting or a Terminal setting.
Any help would be greatly appreciated.
Update 1: Tried this with no luck:
how to change the working directory to the location of the program
The directory field was blank, so I thought this would the solution, but filling it in with the suggestion did nothing to alleviate the issue.
Update 2:
Just tried deleting the preference file, still no solution. I'm willing to give someone reputation. I don't have a whole lot because I'm a newer member, but I'll give what the person thinks is fair, to whoever solves it. I'm desperate and really don't want to wait 2 days to have this issue solved.
Update 3:
Tried changing the default path in the "Profile (release)->options area in the scheme section to the default variable suggested in update 1. No luck. I'm beginning to lose my mind.
Update 4:
I've tried deleting the scheme entirely and making a new one, in hopes that maybe there was something botched with the scheme, but this did not solve the issue. Input and output while running the app in Xcode is still using the working directory, while running the executable in the debug folder is using the home folder.
Update 5:
Just tested this on an older iMac and Xcode setup (OS 10.8.5 and Xcode 5.1.1) and it seems to be working correctly, reading and writing to the current working directory of the application in the debug folder.
For whatever reason, the solution suggested by https://stackoverflow.com/a/15537436/1035008 no longer works. Maybe broken in Xcode 8.1. But this seems to work:
#include <iostream>
#include <fstream>
#include <unistd.h>
using namespace std;
int main (int argc, const char * argv[])
{
// argv[0] returns the full path to the program, in my case "/Users/yuchen/Library/Developer/Xcode/DerivedData/../Debug/test
string directory(argv[0]);
// And we want to get rid of the program name `test`
directory = directory.substr(0, directory.find_last_of("/"));
// Point the directory to the program directory
chdir(directory.c_str());
cout << "Current directory is: " << getcwd(NULL, 0) << endl; // /Users/yuchen/Library/Developer/Xcode/DerivedData/../Debug/
ifstream fin("hi.txt");
if (fin.is_open()) cout << "File is Open" << endl;
else cout << "File is not open" << endl;
fin.close();
return 0;
}
Also see SO and SO. Hope this helps.
I am having trouble executing my C++ code. I have written a basic "Hello World" program, and compiled it using the g++ make command. Here is my code:
#include <iostream>
using namespace std;
int main() {
cout << "Hello World" << endl;
return 0;
}
I am on Windows 10, using Emacs for code editing, and CygWin for compilation. I saved this file as hello.cpp. I then navigated to the directory in CygWin. Then I did the command make hello. This created hello.exe. Then, I attempted to execute the file using ./hello.exe. I also tried ./hello which also didn't work. When I type one of these commands and hit Enter, it just on the next line, not doing anything. I can type in this blank line, but it won't do anything. Does anyone know a way to make my code execute properly. Thank you.
EDIT: I tried running this at cpp.sh, an online C++ compiler, and it worked fine.
Your program probably is working but the console window is closing before you can see anything.
Try adding an input at the end of the program so it will wait.
I.E.
int a;
cin >> a;
Your code is most likely executing, but not outputting anything. That's because it's failing. Try checking the return value after it has run with echo $?. If it's not 0 then it has crashed. Also run it in gdb and see if it fails. The reason why it's failing is most likely a windows/cygwin clash - it's not your code.
Like the questioner in "New to Xcode can't open files in c++?" I'm learning Xcode and OS X (I'm using Xcode 7 on a Yosemite mac).
I can get the code to work perfectly when I build and run it, but can't get the executable to work when I try to run it as a stand alone program.
I'm trying to translate some games I've written on a PC in C++ using SFML.
There has to be a way to save high scores and previous games within an app, but this has me stymied.
This is the sample code I used based on the previous question:
#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;
fin.close();
fout.open("outputFile.txt");
fout << input;
fout << "\n Data transferred \n";
fout.close();
}
This works perfectly when I build and run it, so I've got the proper path to the desktop folder set up. (I'm putting the data files in the same folder as the executable and specifying the path in Xcode.)
No problems when I run this within Xcode, but this is the message on the terminal console when I run the executable by itself:
"…/Desktop/datafiles/Build/Products/Debug/datafiles ; exit;
…/Desktop/datafiles/Build/Products/Debug/datafiles ; exit;
File failed to open.
logout
Saving session...
...copying shared history...
...saving history...truncating history files...
...completed.
[Process completed]"
Is there another flag or path that needs to be set within Xcode for this to work? Two other related questions: How do I access the terminal history to see what is going on? Finally, if I set up the project as an SFML app instead of a terminal project (command line tool app), why can't I see the files within the SFML app, even though I've set the command line flag to see hidden files, and I can see other hidden files on my hard drive? I can see the files if I open the SFML app folder in Windows, so I know they are there.
This is my first question on Stack Overflow, so apologies if this should be appended to the previous question, but this doesn't appear to be an answer to me, but is quite a different version of the original question that is not addressed in the answers.
Thanks!
I really like Sublime Text 2 for HTML/CSS and Python and I'm starting to learn C++ and I want to use Sublime Text 2. I have looked at a few tutorials on installing g++ in order to run C++ in Sublime Text 2.
This is my code:
// my first program in C++
#include <iostream>
int main()
{
std::cout << "Hello World!";
}
And when I run it it says [Finished in 1.5s] but nothing got printed. I have added the environment variables path but nothing gets printed.
The problem is that you are pressing build, which compiles your source code into an executable but does not run it. The [Finished in ...s] you are seeing is how long the program took to compile.
What you need to do is build like you currently are, but then go to the directory where your source code is and run the executable file that's in there*. There is a run option within the editor, but it doesn't always work on Windows**.
*if the program closes instantly, try running it from the console or adding std::cin.get() to the end of your program
**often due to incorrect configuration