I have to do a programming project for an optimisation class, that has to be written in C or C++. So I'm trying to figure out Visual Studio 2015. I created a blank project, and opened a new C++ file, where I have the following:
#include <iostream>
int main()
{
cout >> "Hello World!/n";
cin.get();
return 0;
}
When I run it, I get a large blank white popup, and nothing else happens, even if I hit various key on the keyboard or wait for several minutes. It looks like this:
If I close the large popup, nothing happens. What Visual Studio refers to as output from build looks like this:
1>------ Deploy started: Project: LinearProgramming, Configuration: Debug Win32 ------
1>Updating the layout...
1>Deployment complete (157ms). Full package name: "53acc796-5708-4314-9034-f2a1f840a4f4_1.0.0.0_x86__eazt3av84y7ym"
========== Deploy: 1 succeeded, 0 failed, 0 skipped ==========
Could anyone please explain to me what's going on? How can I create a simple C++ project in Visual Studio 2015 and run it?
I believe you selected the "Blank App(Universal Windows)" project template, which is like a Microsoft store application. What you probably want is the "Win32 Console Application" template, which creates an application without its own window (and uses the console for I/O).
This is how I create a Win32 Console Application.
Go to File->New->Project...
Select Visual C++->Win32->Win32 Console Application and name the project.
In the Win32 Application Wizard press the Next > button and be sure Console application and Empty project are selected, and then hit the finish button.
In the Solution Explorer right click on Source Files and select Add->New Item...
Select the C++ File (.cpp), name it, and hit the Add button.
After you change the >> to << add the code above and it should run.
The quick answer is to hit ctrl-f5 to open the console. After running your script and showing your output it waits for you to hit a key before closing the console.
I eventually found the answer to the question which can be seen at How to keep the console window open in Visual C++?
Related
As I often test my binaries inside/outside Microsoft Visual Studio 2017, I want to control the behavior of my code in C/C++ console projects.
One for code for when I run .exe from within Visual Studio in Release mode.
Another when I just click my .exe from Explorer.
What flag or function should I use to know if my .exe was started from inside Visual Studio or not.
What I would like to achive is the:
#if !_RELEASE
system("pause"); // prevents auto shutdown of my .exe in Explorer
// double click
#endif
where _RELEASE is some kind of trait that triggers code in Studio launches,
but not visible in Explorer double click.
What flag or function should I use to know if my process was startded from inside Visual Studio or not.
You shouldn't do such behavior control from inside your program code. That's bad design, and clutters your program code with decisions that should be left on the caller.
I'd recommend if you need different behaviors of your program (e.g. running in background or with visible GUI), this should be controlled with e.g. configuration files or command line parameters.
You can do that for both, Visual Studio settings to specify cmd line parameters, or using a different configuration file, or even a combination of both.
As you seem to insist for a solution of your idea how to fiddle with this in the best way:
You can use the WINAPI functions to iterate through your parent process IDs and check if one of these is matching the "Visual Studio" module.
Here's a Q&A which links to the technique:
How can I reliably check whether one Windows process is the parent of another in C++?
It not exactly solution, but:
Raymond Chen(Microsoft winapi guru*) is most close in spirit to the problem I facing, helping me detect in what mode or circumstances I run my console session.
How can I tell whether my console program was launched from Explorer or from a command prompt?
printf("this process = %d\n", GetCurrentProcessId());
DWORD count = GetConsoleProcessList(nullptr, 0);
if (count == 1) {
printf("I'm the last one!\n");
Sleep(2000);
}
else {
printf("I'm not the last one! %d\n", count);
}
I want to make a console application in C++ and then when the information is displayed, close the console and run in background. Is this possible? Is another way to do that? Python maybe?
You will have to either close the console window while the process is still running, which is system dependent, or start another process, and even though the standard library offers the system function to do that, its argument is a system dependent command line.
So the upshot is: this is system dependent.
In Windows the full-version of Microsoft's Visual Studio IDE has always, as far back as I can remember, used a peculiar approach for this, with two executable files devenv.com and devenv.exe. The former is a console subsystem executable, which by default runs the latter, which is a GUI subsystem executable:
[C:\]
> where devenv
C:\Program Files (x86)\Microsoft Visual Studio 14.0\Common7\IDE\devenv.com
C:\Program Files (x86)\Microsoft Visual Studio 14.0\Common7\IDE\devenv.exe
[C:\]
> _
The basic idea here is that for historical reasons the command interpreter's search for an executable finds the .com file first, so the command devenv just works, either for starting the IDE or just getting the help text via the /? option.
Yes, this is possible with a small variant:
fork another process. But this is heavily system dependent:
posix/linux allow to simply clone the process;
windows requires new process to be created from an executable. You then have to communicate the state. Its less trivial as explained in this article, in the paragraph on porting fork())
then exit the program (it's the only way to give back control to the console).
On Windows use ShowWindow(FindWindowA("ConsoleWindowClass", NULL), false) to hide the console window. It will still be running in the background and is not visible on the taskbar.
However you will have to run a task manager like Taskmgr.exe to find it and shut it down.
#include <windows.h>
#include <iostream>
using namespace std;
int main () {
cout<<"Some information is displayed.. \n\n";
Sleep(5000);
cout<<"wait.. the console is going to hide and run in background.. \n";
Sleep(5000);
ShowWindow(FindWindowA("ConsoleWindowClass", NULL), false);
while(true) {
// Do your hidden stuff in here
}
return 0;
}
The other answers given here overcomplicate things. The most easy way to close the console window in Windows is to simply detach from it. Once the last user of a console window datached, the console window gets closed.
If you start a program from a CLI (e.g. cmd.exe) then this CLI is also attaches to to the console and thus the console window will not close.
Anyway, detaching from a console is as simple as calling
FreeConsole();
… done!
Also you can attach to a newly created console at any time using AttachConsole, which takes a process ID. Now in a CLI situation the parent will usually be the CLI shell, so you may want to attach to the console of that.
When I press the "Local Windows Debugger" button when working on any basic C++ project in Visual Studio 2013, the console opens and the program outputs, but when the console closes, another console opens, the UI changes slightly and the program outputs again.
Steps to reproduce:
Create a new C++ project
Inside the "Source Files" directory of the new project, create a file named "main.cpp"
Put a basic hello world program into the file:
#include <iostream>
using namespace std;
int main() {
cout << "Hello world!";
cin.get();
}
Save the code and press the "Local windows debugger" button on the toolbar
A console opens, and waits until you press enter
After the first console closes, a new one opens up, and the UI changes:
Edit:
Link to download a zip folder containing the project: Test Project.zip
I had avast deepscreen enabled. To disable, goto avast user interface -> Settings -> Antivirus and uncheck the box that says "Enable Deepscreen"
On a new version of avast you need to uncheck CyberCapture option. To disable CyberCapture you need to open Avast->Settings->General and uncheck "Enable CyberCapture"
I had same problem.
Added exception to "c:\source\" where all my visual studio stuff is located.
I have a problem, when I try to open my Hello World.exe file (that I created by following a tutorial). It immediately closes without giving me the chance to read or see if I have done everything correctly.
As you can see, I need help on how to keep it open, without instantly closing.
You can either put a break point before the end of main or try the following:
int main()
{
//...
std::cin.get();
return 0;
}
It is going to wait for you to press some key to exit the console.
EDIT: It is better to add break point which do not change existing code.
In console applications there are a couple of things you can do to stop the window from closing on you such as using system("pause") (not so recommended though), getch(), std::cin >> x etc at the end of the application.
Another option is to start a cmd window, cd to the location of the exe and run it like any other console application is meant to be ran, that way it wont just close on you, it'll simply exit.
In VS2017, you can specify that the executable is a Console app, not a Windows app. This makes your application run in a "Microsoft Visual Studio Debug Console", with "Press Any Key To Close This Window" appearing at the end of the console output:
Right click the project to bring up Properties.
Linker > System > Subsystem > Select "Console".
Press Apply before closing.
When I write a program using C++ and I want to run it, I can't catch the console window. I press CTRLF5 and it does not work.
I want the window to stay open and wait, even it finishes executing. Can anyone help me?
Thanks in advance.
http://connect.microsoft.com/VisualStudio/feedback/details/540969/missing-press-any-key-to-continue-when-lauching-with-ctrl-f5
In the older versions it would default to the console subsystem even if you selected "empty project", but not in 2010, so you have to set it manually. To do this select the project in the solution explorer on the right or left (probably is already selected so you don't have to worry about this). Then select "project" from the menu bar drop down menus, then select "*project_name* properties" > "configuration properties" > "linker" > "system" and set the first property, the drop down "subsystem" property to "console (/SUBSYSTEM:CONSOLE)". The console window should now stay open after execution as usual.
try using system("Pause"); as the last line on your code (before the return of your main function)
Ctrl+F5 should work. Just in case, if you have the source of your program, add the following just before the closing brace of main.
int x;
cin >> x;
the program will wait for you to enter some value.
If you want a breakpoint to be triggerred in debugger, do simple F5 instead of Ctrl+F5, after putting a breakpoint on the relevant source line (assuming the source/debug symbols are available)
Sorry to say, Ruba, but it looks like Microsoft removed this nifty little feature when moving from VS2008 to VS2010.
I can't find anything on MSDN, the web in general, or VS options to turn it back on.
My advice is to bypass the environment altogether for testing your application. Simply open a cmd.exe window in your runtime directory (debug or release or whatever), build the executable within the IDE then switch to the command window and enter testprog.exe to run your program.
Make sure you include any required command line parameters and, after you've entered it the first time, you can just use the up-arrow to retrieve the last command.
Yes, it's a bit of a pain but, until someone comes up with a better solution, it's probably the best way to ensure you see all the output while ensuring the program has shut down completely.
Just set a breakpoint at main()'s closing curly brace if you want to see the console after the program is finished.
You should create VS 2010 C++ Projects as below:
New project -> Visual C++ -> Win32 -> Win32ConsoleApplication
In this way you will be getting "Press any key to continue..." when you run program with ctrl+F5, as it was in VS 2008.
EDIT :
New project -> Visual C++ -> Win32 -> Win32ConsoleApplication -> Next -> Check 'Empty project' -> Finish = what you actually need.