Pause Console in C program

Question

Which is best way to pause the console in C   programs    using cin get   or using system  pause   or using C functions like getch   or getchar      Is it true that use of system  pause   leads to non portable code and can t work in UNIX   Is cin get   is better to use to pause console

User · Answer

There is no good way to do that  but you should use portable solution  so avoid system   calls  in your case you could use cin get   or getch   as you mentioned in your question  also there is one advice  Make all pauses controlled by one  or very few  preprocessor definitions   For example   Somewhere in global file    define USE PAUSES  ifndef  DEBUG      I asume you have  DEBUG definition for debug and don t have it for release build  undef USE PAUSES  endif   Somewhere in code   ifdef USE PAUSES cin get     endif   This is not universal advice  but you should protect yourself from putting pauses in release builds and these should have easy control  my mentioned global file may not be so global  because changes in that may cause really long compilation

User · Answer

This works for me   void pause         cin clear        cin ignore numeric limits lt streamsize gt   max      n        std  string dummy      std  cout  lt  lt   Press any key to continue             std  getline std  cin  dummy

User · Answer

The best way depends a lot on the platform s  being targeted  debug vs  release usage etc   I don t think there is one best way  but to  force  a wait on enter type scenario in a fairly generic way  especially when debugging  typically this is either compiled in or out based on NDEBUG or  DEBUG   you could try std  getline as follows  inline void wait on enter         std  string dummy      std  cout  lt  lt   Enter to continue      lt  lt  std  endl      std  getline std  cin  dummy       With our without the  enter to continue   as needed

User · Answer

There might be a best way  like using the portable cin get     but a good way doesn t exist  A program that has done its job should quit and give its resources back to the computer   And yes  any usage of system   leads to unportable code  as the parameter is passed to the shell that owns your process   Having pausing-code in your source code sooner or later causes hassles    someone forgets to delete the pausing code before checking in   now all working mates have to wonder why the app does not close anymore version history is tainted   define is hell it s annoying to anyone who runs your code from the console it s very  very  very annoying when trying to start and end your program from within a script  quadly annoying if your program is part of a pipeline in the shell  because if the program does not end  the shell script or pipeline won t  too   Instead  explore your IDE  It probably has an option not to close the console window after running  If not  it s a great justification to you as a developer worth her his money to always have a console window open nearby   Alternatively  you can make this a program option  but I personally have never seen a program with an option --keep-alive-when-dead   Moral of the story  This is the user s problem  and not the program s problem  Don t taint your code

User · Answer

I always used a couple lines of code which clear the input stream of any characters and then wait for input to ignore   Something like   void pause         cin clear        cout  lt  lt  endl  lt  lt   Press any key to continue          cin ignore        And then any time I need it in the program I have my own pause    function  without the overhead of a system pause  This is only really an issue when writing console programs that you want to stay open or stay fixated on a certain point though

User · Answer

If you want to write portable C   code  then I d suggest using cin get     system  PAUSE   works on Windows  since it requires the execution of a console command named  PAUSE   But I m not sure that other operating systems like Linux or other Unix derivatives support that  So that tends to be non-portable   Since C   already offers cin get    I see no compelling reason to use C getch

User · Answer

My answer is partially based on that from Yoank  and partially on a comment by Justin Time on another question    cout  lt  lt  endl  lt  lt   Press  lt Enter gt  to continue      cin ignore numeric limits lt streamsize gt   max      n    cin get

User · Answer

Which is best way to pause the console in C   programs    system  pause    and getch     which comes from the DOS world  IIRC  are both unportable      Is cin get   is better to use to pause console     As the only one portable and standard option  I would say it is  but I personally believe one should not write interactive console programs  i e  programs which actually pause the console or prompt for input  unless there is a really good reason for that  because that makes shell scripting much harder   Console programs should interact with the user via command line arguments  or at least that kind of interaction should be the default one    Just in case you need pausing the program for the my-program-is-launched-from-the-IDE-and-immediately-closed-but-I-don t-have-enough-time-to-see-the-result reason  mdash  don t do that  Just configure your IDE or launch console programs right from the console

User · Answer

I just want to add that there is a way to get what you want  but it will require to use some a third party library  or that you write the platform dependent code yourself    As far as I m concerned  the biggest drawback with cin is that you are required to hit Return  and not just any key    Assuming you had a key-listener you could quite easily write a function that waits for the user to hit any key  However finding a platform independent key listener is no trivial task  and will most likely require you to load parts of a larger library   I am thinking something along the lines of   char wait for key         int key      while      key    key pressed ANY                 this thread  yield              return convert virtual key to char key       The actual function would obviously be quite different from what I wrote  depending on the library you use   I know the following libraries have keylisteners  Feel free to add more in an edit if you know of any      keycode SDL

User · Answer

Late response  but I think it will help others   Part of imitating system  pause   is imitating what it asks the user to do   Press any key to continue         So  we need something that does not wait for simply a return as std  cin get   would do  Even getch   has its problems when used twice  the second time call has been noticed to skip pausing generally if it s immediately paused again afterwards on the same key press   I think it has to do with the input buffer  System  pause   is usually not recommended  but we still need something to imitate what users might already expect  I prefer getch   because it doesn t echo to the screen  and it works dynamically    The solution is to do the following using a do-while loop   void Console  pause          int ch   0       std  cout  lt  lt    nPress any key to continue               do           ch   getch          while  ch    0        std  cout  lt  lt  std  endl       Now it waits for the user to press any key  If it s used twice  it waits for the user again instead of skipping

[c++] Pause Console in C++ program

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