217

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?

Peter Mortensen
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Adam P
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    Are you double-clicking the executable? Are you working in Windows? Why aren't you working from the Command shell and typing in the commands as you want them executed? – S.Lott Mar 27 '10 at 14:34
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    @S Lott: Because if you push the "Go" button in your IDE you don't need to bother with a console. – Billy ONeal Mar 27 '10 at 14:38
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    You should consider getting a good book from which to learn C++. Websites are good resources, but are no match for a good introductory text. There's a definitive list of C++ books here: http://stackoverflow.com/questions/388242/the-definitive-c-book-guide-and-list – James McNellis Mar 27 '10 at 14:39
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    @Billy If pressing the Go button closes the app when it terminates, you are using the wrong IDE. –  Mar 27 '10 at 14:48
  • @Neil Butterworth: I agree that it sucks but that is Visual Studio's default behavior. – Billy ONeal Mar 27 '10 at 15:05
  • @Billy Really? well things have gone backwards in VS land. I haven't used it since VC++ 6.0, but in that version, the IDE handles keeping the console open for you. –  Mar 27 '10 at 15:07
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    Asked and answered previously here: http://stackoverflow.com/questions/902261/is-there-a-decent-wait-function-in-c , though this one has a better title. – dmckee --- ex-moderator kitten Mar 27 '10 at 15:33
  • @Neil... it depends whether you are debugging or not... if not debugging it'll keep it open for you. And I bet there is some setting for this as well, but I don't feel like digging for it. – DigitalZebra Mar 27 '10 at 16:09
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    possible duplicate of [Preventing console window from closing on Visual Studio C/C++ Console application](http://stackoverflow.com/questions/1775865/preventing-console-window-from-closing-on-visual-studio-c-c-console-applicatio) – user Mar 09 '14 at 22:43

35 Answers35

143

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.

nabulke
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136

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.

Community
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James McNellis
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  • This is probably the better of the two answers right now, but I would probably put a comment next to that to tell why you're actually doing it in real code. +1. – Billy ONeal Mar 27 '10 at 14:39
  • Another variant of this sort if to "#include " and use _getch(). – Poni Mar 27 '10 at 14:41
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    `getchar` does not solve the problem - or only in limited circumstances, at least. It reads a char from `stdin`, but if there are already characters buffered from stdin the program will carry on without waiting regardless of whether you print a prompt or not. – CB Bailey Mar 27 '10 at 14:46
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    @Charles: A good point. Ignoring until `\n` is a partial solution, but won't help if more than one line of input is buffered. I do not know of a standard C++ way to clear everything from an input stream. :-/ – James McNellis Mar 27 '10 at 15:44
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    @James: Old, but how about `std::cin.ignore(std::cin.rdbuf()->in_avail());`? Got it from [here](http://stackoverflow.com/questions/257091/how-do-i-flush-the-cin-buffer/538629#538629). – GManNickG Oct 03 '10 at 10:35
  • @GMan: I don't think that actually works: the streambuf probably isn't the only buffer between the input device and `cin`; the OS is probably doing other buffering in the background and there is no standard way to inspect that buffer.r – James McNellis Oct 04 '10 at 03:45
  • @James: `while (std::cin.rdbuf()->in_avail()) std::cin.ignore(std::cin.rdbuf()->in_avail());`? :S This should really be simpler. – GManNickG Oct 04 '10 at 03:51
  • @GMan: It depends on how buffering is handled by the system. One case where that solution will fail: the OS has its own buffer that is used when `cin.rdbuf()` is full. You check `in_avail()`; it's full and greater than zero so you call `ignore(in_avail())` and clear the buffer; you check `in_avail()` again and it is now zero and you break out of the loop. But, meanwhile, you've typed stuff in and the OS hasn't started putting new characters into `cin.rdbuf()`. I think it's entirely dependent upon how the system buffers stdin; I'm not all that familiar with how modern systems do that. – James McNellis Oct 04 '10 at 05:13
  • [I do so little work with console input and output, I just don't know much about the details of this. And, if it were simpler, it would be C# :-P (I kid, I kid! Sort of...)] – James McNellis Oct 04 '10 at 05:14
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    One option I use alot is `std::cin.ignore(std::numeric_limits::max(), '\n');` with `#include `. – Xeo Jan 29 '11 at 07:42
  • @Xeo: That works unless there are multiple lines of data buffered in stdin. – James McNellis Jan 29 '11 at 07:43
  • @James: Really? I always thought it ignores `'\n'` times `std::numeric_limits::max()`... Seems I still know little 'bout the standard library. – Xeo Jan 29 '11 at 07:46
  • @Xeo: It ignores characters until it has read N characters (`std::numeric_limits::max()` in your example) or it reads the sentinel value (`'\n'`), whichever comes first. – James McNellis Jan 29 '11 at 07:48
  • @James: You're right, but wouldn't a simple `std::cin.ignore(std::numeric_limits::max())` be sufficient then? The default delimiter for ignore(...) is EOF. Of course it does not work if you have EOF in the stdin buffer, but usually that shouldn't happen? EDIT: Screw that, I just thought that over.. – Xeo Jan 29 '11 at 07:54
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    Please don't do this. :( It's not part of your program's function to do this. – Lightness Races in Orbit Dec 23 '11 at 11:42
  • @nabulke is much easier in case you are using VS IDE, else system("pause"); is right answer – Furkat U. Aug 07 '13 at 07:01
  • Downvoted because adding stopping code is Very Bad Advice. – Cheers and hth. - Alf Jan 07 '18 at 09:38
132

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 . . .

Billy ONeal
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codaddict
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    That sounds like a Rube Goldberg variation of a solution. – Dave Van den Eynde Mar 27 '10 at 14:36
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    @Dave Van den Eynde: It's also quite common and comes standard in the boilerplate code in DevCPP. +1 – Billy ONeal Mar 27 '10 at 14:37
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    @Dave on the other hand it does make it clear that this is just a bodge for an example, while std:getch could be accidentally left in real code. – Martin Beckett Mar 27 '10 at 17:10
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    This is a perfectly valid solution for those on Windows. Whilst not ideal, it does work – thecoshman Oct 10 '12 at 13:12
  • Easiest, quickest, solution. Just what I needed – CodyBugstein Dec 18 '13 at 12:53
  • I found this useful with Visual Studio since CTRL-F5 would close the console if I needed to enter an input value from the command line. – P. Mink Jun 02 '18 at 16:54
  • @eaglei22 it's platform specific and it's functionality might change if MS ever decide to change what `pause` does, or even remove it. – thecoshman Oct 10 '18 at 14:59
  • @thecoshman Ah okay, that makes sense. Thanks for following up! – eaglei22 Oct 10 '18 at 15:09
  • Coming here from a link in [SO: Why doesn't my program output the information I want in outside of Visual Studios 2019?](https://stackoverflow.com/q/55675651/7478597)... Please note [**ENV33-C. Do not call system()**](https://wiki.sei.cmu.edu/confluence/pages/viewpage.action?pageId=87152177). It's C++. A simple `{ std::cout << "Press [ENTER] to continue..."; std::string line; std::getline(std::cin, line); }` would do as well and is surely much less vulnerable. – Scheff's Cat Apr 14 '19 at 14:52
86

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.

MicroVirus
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Mr. Underhill
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20

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.

John Dibling
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15

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.

Amos
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    Because if you are using an IDE you don't generally use a console. You push go, the program runs, and that's it. – Billy ONeal Mar 27 '10 at 14:40
  • +1: Blindly using IDE isn't really all that helpful. Using a console to run console applications seems appropriate. – S.Lott Mar 27 '10 at 14:44
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    Any competent IDE will keep the console on screen when the app terminates - Code::Blocks for example does exactly this. –  Mar 27 '10 at 14:49
  • @Neil Butterworth: Visual Studio does not, and I suspect that's what the OP is using. Though I agree with you that it should. – Billy ONeal Mar 27 '10 at 15:04
  • If VS can't be configured to keep the window open, then use the console itself. – S.Lott Mar 27 '10 at 15:11
  • @Billy: VS does too, press Ctrl+F5. If you use Start Debugging (F5), it assumes you actually want to debug the program. – Hans Passant Mar 27 '10 at 16:08
  • @nobugz: Unless I've screwed something up on my installation, which is quite possible, that is not the behavior in Visual Studio 2010 and I would have sworn that it's not the behavior of 2008. Is that a configurable option, do you know? – James McNellis Mar 27 '10 at 16:13
  • @James: not that I'm aware of, I've never seen or heard it not work. – Hans Passant Mar 27 '10 at 17:11
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    @nobugz: I figured it out. To get the window to stick around, you have to have /SUBSYSTEM:CONSOLE on the linker command line. The documentation says that this is the default if `main` is defined, but if I don't explicitly set it on the command line, VS kills the window when the application exits. *sigh* – James McNellis Mar 27 '10 at 17:23
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    @James: that is required to get a console window in the first place. That in turn requires main() instead of WinMain(), not the other way around. I'm a bit lost... – Hans Passant Mar 27 '10 at 17:32
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    @nobugz: If you start from an "Empty Project" instead of a "Win32 Console Application" the subsystem is not explicitly set in the project properties. If you define `main` in the project, the linker by default uses the CONSOLE subsystem. When debugging or running, you'll get a console window. However, unless you explicitly specify CONSOLE as the subsystem in the project properties, Visual Studio will not keep the console window open. I always start from an empty project and I rarely change individual project properties, so I've never seen the console window stick around. Sorry for the confusion – James McNellis Mar 27 '10 at 17:55
  • @James: If Visual Studio doesn't know you've got a console application, then Windows itself is allocating the console when the app starts, in which case it is also destroyed when the app exits. – Ben Voigt Mar 28 '10 at 23:15
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    James is right. I had the same problem with a "project from existing code" and setting the subsystem (which was blank) fixed it. – Matt Chambers Sep 13 '11 at 18:16
12

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
}
Peter Mortensen
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robert
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9

Call cin.get(); 2 times:

    //...
    cin.get();
    cin.get();
    return 0
}
Shadow The GPT Wizard
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tsx
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  • what if we need another cin.get() for getting for example some string inside array before this? It's not work in this scenario. – QMaster Jun 16 '15 at 14:33
4

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.

4

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.

3

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.

DigitalZebra
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3

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();
Bat_Programmer
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2

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.

Kate Gregory
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2

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");
Thomas Matthews
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2

simply

#include <cstdio>

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

for some reason there is usually 1 character possible to read with getchar already in stdin when you run a program. so the first getchar reads this character, and the second getchar waits for user (your) input before exiting the program. And after a program exits most of terminals, especially on Windows close terminal immediately. so what we aim to is a simple way of preventing a program from finishing after it outputs everything. Of course there are more complex and clean ways to solve this, but this is the simplest.

2

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).

MicroVirus
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2

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");
}
David Doria
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1

Similar idea to yeh answer, just minimalist alternative.

Create a batch file with the following content:

helloworld.exe
pause

Then use the batch file.

Cœur
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0

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
Peter Mortensen
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yeh
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  • This is a bad solution AND it's bad batch code. A better solution would be to just use `system("pause >nul")` – madladzen Oct 25 '20 at 18:25
0

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....

Peter Mortensen
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0

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.

Tronic
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0

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

Peter Mortensen
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lierosk
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    This does not provide an answer to the question. To critique or request clarification from an author, leave a comment below their post - you can always comment on your own posts, and once you have sufficient [reputation](http://stackoverflow.com/help/whats-reputation) you will be able to [comment on any post](http://stackoverflow.com/help/privileges/comment). – Ravi Dhoriya ツ Dec 18 '14 at 11:58
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    How this doesnt provide answer? Im in exactly same situation like author of a question and this helps. – lierosk Dec 18 '14 at 13:54
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.

QMaster
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0

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

Nathan Tuggy
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0

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!!!!)

anony
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0

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

main()
  {
  //your codes 

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

  return 0;
  }

thats all

Zen Of Kursat
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0

you can try also doing this

sleep (50000);
cout << "any text" << endl;

This will hold your code for 50000m, then prints message and closes. But please keep in mind that it will not pause forever.

prigadiri
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0

Here's a problem, not so obvious. Somehow I had added a debug breakpoint at the very last line of my program. } Not sure how I did that, perhaps with an erroneous mouse click while jumping between different screens. I'm working in VS Code.

And when I go to debug, the system jumps immediately to that breakpoint. No error message, no interim output, nothing. I'm like, how did the program rush thru all my set breakpoints? This took too long to figure out.

Apparently the system sees that last line breakpoint as a "first" stop. The simple fix? Delete that breakpoint, doh! (insert forehead slap here.)

zipzit
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0

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.

Northcode
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    2 is sometimes also not enough (when there are more key strokes queued). The correct way is to ignore as many characters as are in the queue. To with, `cin.rdbuf()->in_avail`. Not some magic number like 1 or 2. – Konrad Rudolph Dec 31 '11 at 22:35
-1

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;
nbrooks
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-1

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.

Peter Mortensen
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Izza
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-2

Include conio.h and at the end of your code, before return 0, write _getch();

Zach Saucier
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Ali Asgari
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-3

You could also stick

while(true)
    ;

or

for(;;)
    ;

at the end.

Peter Mortensen
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Roman A. Taycher
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    -1 Busy spins are evil. They consume your CPU cycles and accomplish nothing. If you are going to do something like this, at least put a call to pause inside the loop body to yield the majority of your cycles. – Nathan Mar 29 '13 at 18:38
-3

Start in debug mode, run code with F5 to stop your console app, don't click on red cross but press CTRL-break and you'll hit all breakpoints in the end of your program.

Daan
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-5

simply put this at the end of your code:

while(1){ }

this function will keep going on forever(or until you close the console) and will keep the console it from closing on its own.