Question

Lately, I've been trying to learn C++ from this website. Unfortunately whenever I try to run one of the code samples, I see that program open for about a half second and then immediately close. Is there a way to stop the program from closing immediately so that I can see the fruits of my effort?

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Solution

Edit: As Charles Bailey rightly points out in a comment below, this won't work if there are characters buffered in stdin, and there's really no good way to work around that. If you're running with a debugger attached, John Dibling's suggested solution is probably the cleanest solution to your problem.

That said, I'll leave this here and maybe someone else will find it useful. I've used it a lot as a quick hack of sorts when writing tests during development.


At the end of your main function, you can call std::getchar();

This will get a single character from stdin, thus giving you the "press any key to continue" sort of behavior (if you actually want a "press any key" message, you'll have to print one yourself).

You need to #include <cstdio> for getchar.

OTHER TIPS

If you are using Visual Studio and you are starting the console application out of the IDE:

pressing CTRL-F5 (start without debugging) will start the application and keep the console window open until you press any key.

The solution by James works for all Platforms.

Alternatively on Windows you can also add the following just before you return from main function:

  system("pause");

This will run the pause command which waits till you press a key and also displays a nice message Press any key to continue . . .

If you are using Microsoft's Visual C++ 2010 Express and run into the issue with CTRL+F5 not working for keeping the console open after the program has terminated, take a look at this MSDN thread.

Likely your IDE is set to close the console after a CTRL+F5 run; in fact, an "Empty Project" in Visual C++ 2010 closes the console by default. To change this, do as the Microsoft Moderator suggested:

Please right click your project name and go to Properties page, please expand Configuration Properties -> Linker -> System, please select Console (/SUBSYSTEM:CONSOLE) in SubSystem dropdown. Because, by default, the Empty project does not specify it.

I usually just put a breakpoint on main()'s closing curly brace. When the end of the program is reached by whatever means the breakpoint will hit and you can ALT-Tab to the console window to view the output.

Why not just run the program from a console ie run the program from cmd.exe if you're using Windows. That way the window stays open after the program finishes.

[EDIT]: When I use KDevelop4 there is a fully fledged instance of Bash (a Linux CLI) running in a tab at the bottom of the IDE. Which is what I use in these sort of circumstances.

Before the end of your code, insert this line:

system("pause");

This will keep the console until you hit a key.

#include <iostream>
#include <string>

using namespace std;

int main()
{
    string s;
    cout << "Please enter your first name followed by a newline\n";
    cin >> s;
    cout << "Hello, " << s << '\n';
    system("pause"); // <----------------------------------
    return 0; // This return statement isn't necessary
}

Call cin.get(); 2 times:

    //...
    cin.get();
    cin.get();
    return 0
}

If you run your code from a competent IDE, such as Code::Blocks, the IDE will manage the console it uses to run the code, keeping it open when the application closes. You don't want to add special code to keep the console open, because this will prevent it functioning correctly when you use it for real, outside of the IDE.

Okay I'm guessing you are on Windows using Visual Studio... why? Well because if you are on some sort of Linux OS then you'd probably be running it from the console.

Anyways, you can add crap to the end of your program like others are suggesting, or you can just hit CTRL + F5 (start without debugging) and Visual Studio will leave the console up once complete.

Another option if you want to run the Debug version and not add crap to your code is to open the console window (Start -> Run -> cmd) and navigate to your Debug output directory. Then, just enter the name of your executable and it will run your debug program in the console. You can then use Visual Studio's attach to process or something if you really want to.

If you are actually debugging your application in Visual C++, press F5 or the green triangle on the toolbar. If you aren't really debugging it (you have no breakpoints set), press Ctrl+F5 or choose Start Without Debugging on the menus (it's usually on the Debug menu, which I agree is confusing.) It will be a little faster, and more importantly to you, will pause at the end without you having to change your code.

Alternatively, open a command prompt, navigate to the folder where your exe is, and run it by typing its name. That way when it's finished running the command prompt doesn't close and you can see the output. I prefer both of these methods to adding code that stops the app just as its finished.

Just add the following at the end of your program. It will try to capture some form of user input thus it stops the console from closing automatically.

cin.get();

Add the following lines before any exit() function or before any returns in main():

std::cout << "Paused, press ENTER to continue." << std::endl;
cin.ignore(100000, "\n");

For Visual Studio (and only Visual Studio) the following code snippet gives you a 'wait for keypress to continue' prompt that truly waits for the user to press a new key explicitly, by first flushing the input buffer:

#include <cstdio>
#include <tchar.h>
#include <conio.h>

_tprintf(_T("Press a key to continue "));
while( _kbhit() /* defined in conio.h */ ) _gettch();
_gettch();

Note that this uses the tchar.h macro's to be compatible with multiple 'character sets' (as VC++ calls them).

I just do this:

//clear buffer, wait for input to close program
std::cin.clear(); std::cin.ignore(INT_MAX, '\n');
std::cin.get();
return 0;

Note: clearing the cin buffer and such is only necessary if you've used cin at some point earlier in your program. Also using std::numeric_limits::max() is probably better then INT_MAX, but it's a bit wordy and usually unnecessary.

Use #include "stdafx.h" & system("pause"); just like the code down below.

#include "stdafx.h"
#include <iostream>
using namespace std;
int main()
{
    std::cout << "hello programmer!\n\nEnter 2 numbers: ";
    int x, y;
    std::cin >> x >> y;
    int w = x*y;
    std::cout <<"\nyour answer is: "<< w << endl;
    system("pause");
}
#include "stdafx.h"
#include <iostream>
#include <conio.h>

using namespace std;

int main()
{

    cout << "Press any key to continue...";
    getch();

    return 0;
}

I didnt notice anyone else post this so here it is.

Similar idea to yeh answer, just minimalist alternative.

Create a batch file with the following content:

helloworld.exe
pause

Then use the batch file.

See if your IDE has a checkbox in project setting to keep the window open after the program terminates. If not, use std::cin.get(); to read a character at the end of main function. However, be sure to use only line-based input (std::getline) or to deal with leftover unread characters otherwise (std::ignore until newline) because otherwise the .get() at the end will only read the garbage you left unread earlier.

This seems to work well:

cin.clear();
cin.ignore(2);

If you clear the buffer first it won't be a problem when you read the next one. For some reason cin.ignore(1) does not work, it has to be 2.

You could always just create a batch file. For example, if your program is called helloworld.exe, some code would be:

@echo off
:1
cls
call helloworld.exe
pause >nul
goto :1

If you are running Windows, then you can do system("pause >nul"); or system("pause");. It executes a console command to pause the program until you press a key. >nul prevents it from saying Press any key to continue....

I'm putting a breakpoint at the last return 0 of the program. It works fine.

simply

int main(){
    // code...
    getchar();
    getchar();
    return 0;
}

I used cin.get() and that is worked but one day I needed to use another cin.get([Array Variable]) before that to grab a ling string with blank character in middle of. so the cin.get() didn't avoid command prompt window from closing. Finally I found Another way: Press CTRL+F5 to open in an external window and Visual Studio does not have control over it anymore. Just will ask you about closing after final commands run.

I tried putting a getchar() function at the end. But it didn't work. So what I did was add two getchar() functions one after another. I think the first getchar() absorbs the Enter key you press after the last data input. So try adding two getchar() functions instead of one

Instead of pressing the run button, press CTRL and F5 at the same time, it will give you the press any key to continue message. Or type "(warning use this only for testing not actual programs as an antiviruses don't like it!!!!)" at the end of your main function but: (warning use this only for testing not actual programs as an antiviruses don't like it!!!!)

just use cin.ignore() right before return 0; twice

main()
  {
  //your codes 

  cin.ignore();
  cin.ignore();

  return 0;
  }

thats all

All you have to do set a variable for x then just type this in before the return 0;

cout<<"\nPress any key and hit enter to end...";
cin>>x;

You can even declare an integer at the beginning of your main() function (say int a;) and put std::cin >> a; just before the return value. So the program will keep running until you press a key and enter.

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