Why is the console window closing immediately once displayed my output

Question

I m studying C  by following the guides in MSDN     Now  I just tried the Example 1  here is the link to MSDN   and I ve encountered an issue  why is the console window closing immediately once displayed my output   using System   public class Hello1       public static int Main                 Console WriteLine  Hello  World             return 0

User · Answer

This behaves the same for CtrlF5 or F5  Place immediately before end of Main method  using System Diagnostics   private static void Main string   args       DoWork         if  Debugger IsAttached        Console WriteLine  quot Press any key to continue       quot        Console ReadKey

User · Answer

Add the following before the return 0   system  PAUSE        This prints a line to hit a key to close the window  It will keep the window up until you hit the enter key   I have my students add it to all their programs

User · Answer

Use Console Read     to prevent the program from closing  but make sure you add the Console Read    code before return statement  or else it will be a unreachable code         Console Read         return 0     check this Console Read

User · Answer

Instead of using  Console Readline   Console Read   Console ReadKey     you can run your program using Ctrl F5  if you are in Visual Studio   Then Visual Studio will keep the console window open  until you press a key   Note  You cannot debug your code in this approach

User · Answer

The code is finished  to continue you need to add this   Console ReadLine      or  Console Read

User · Answer

I m a little bit late to the party  but  in Visual Studio 2019 for  NET Core projects the console doesn t close automatically by default  You can configure the behaviour through menu Tools   Options   Debugging   General   Automatically close the console when debugging stops  If you get your console window automatically closing  check if the mentioned setting is not set   The same applies to the  NET Framework new style console projects    lt Project Sdk  Microsoft NET Sdk  gt      lt PropertyGroup gt       lt OutputType gt Exe lt  OutputType gt       lt TargetFramework gt net472 lt  TargetFramework gt     lt  PropertyGroup gt    lt  Project gt    The old style  NET Framework project still unconditionally close the console at the end  as of Visual Studio 16 0 1    Reference  https   devblogs microsoft com dotnet net-core-tooling-update-for-visual-studio-2019-preview-2

User · Answer

Alternatively  you can delay the closing using the following code   System Threading Thread Sleep 1000     Note the Sleep is using milliseconds

User · Answer

Here is a way to do it without involving Console   var endlessTask   new TaskCompletionSource lt bool gt    Task  endlessTask Wait

User · Answer

Add The Read method to show the output       Console WriteLine  Hello  World     Console Read    return 0

User · Answer

if your program requires you to press enter to continue like you have to enter a value and continue  then add a new double or int  and type write before retunr 0   scanf s   lf   amp the variable

User · Answer

You can solve it very simple way just invoking the input  However  if you press Enter then the console will disapper again  Simply use this Console ReadLine    or Console Read

User · Answer

I always add the following statement to a console application  Create a code snippet for this if you wish   Console WriteLine  Press any key to quit     Console ReadKey      Doing this helps when you want to experiment different concepts through console application    Ctr   F5 will make the Console stay but you cant debug  All the console applications that I have written in realworld is always non-interactive and triggered by a Scheduler such as TWS or CA Work station and did not require something like this

User · Answer

this is the answer async at console app in C    anything whereever in the console app never use await but instead use theAsyncMethod   GetAwaiter   GetResult       example  var result   await HttpClientInstance SendAsync message    becomes  var result   HttpClientInstance SendAsync message  GetAwaiter   GetResult

User · Answer

The program is closing as soon as it s execution is complete  In this case when you return 0   This is expected functionality  If you want to see the output then either run it in a terminal manually or set a wait at the end of the program so that it will stay open for a few seconds   using the threading library

User · Answer

To simplify what others are saying  Use Console ReadKey       This makes it so the program is waiting on the user to press a normal key on the keyboard  Source  I use it in my programs for console applications

User · Answer

The program immediately closes because there s nothing stopping it from closing  Insert a breakpoint at return 0  or add Console Read    before return 0  to prevent the program from closing

User · Answer

According to my concern  if we want to stable the OUTPUT OF CONSOLE APPLICATION  till the close of output display USE  the  label  after the MainMethod  and  goto label   before end of the program  In the Program   eg   static void Main string   args        label          Snippet of code      goto label

User · Answer

I assume the reason you don t want it to close in Debug mode  is because you want to look at the values of variables etc   So it s probably best to just insert a break-point on the closing     of the main function  If you don t need to debug  then Ctrl-F5 is the best option

User · Answer

the issue here is that their Hello World Program is showing up then it would immediately close    why is that    Because it s finished  When console applications have completed executing and return from their main method  the associated console window automatically closes  This is expected behavior   If you want to keep it open for debugging purposes  you ll need to instruct the computer to wait for a key press before ending the app and closing the window   The Console ReadLine method is one way of doing that  Adding this line to the end of your code  just before the return statement  will cause the application to wait for you to press a key before exiting   Alternatively  you could start the application without the debugger attached by pressing Ctrl F5 from within the Visual Studio environment  but this has the obvious disadvantage of preventing you from using the debugging features  which you probably want at your disposal when writing an application   The best compromise is probably to call the Console ReadLine method only when debugging the application by wrapping it in a preprocessor directive  Something like    if DEBUG     Console WriteLine  Press enter to close           Console ReadLine     endif   You might also want the window to stay open if an uncaught exception was thrown  To do that you can put the Console ReadLine    in a finally block    if DEBUG     try                               finally               Console WriteLine  Press enter to close               Console ReadLine           endif

User · Answer

If you want to keep your application opened  you have to do something in order to keep its process alive  The below example is the simplest one  to be put at the end of your program   while  true      However  it ll cause the CPU to overload  as it s therefore forced to iterate infinitely   At this point  you can opt to use System Windows Forms Application class  but it requires you to add System Windows Forms reference    Application Run      This doesn t leak CPU and works successfully     In order to avoid to add System Windows Forms reference  you can use a simple trick  the so-called spin waiting  importing System Threading   SpinWait SpinUntil      gt  false     This also works perfectly  and it basically consists of a while loop with a negated condition that is returned by the above lambda method  Why isn t this overloading CPU  You can look at the source code here  anyway  it basically waits some CPU cycle before iterating over     You can also create a message looper  which peeks the pending messages from the system and processes each of them before passing to the next iteration  as follows    DebuggerHidden  DebuggerStepperBoundary  DebuggerNonUserCode  DllImport  user32 dll   EntryPoint    PeekMessage    public static extern int PeekMessage out NativeMessage lpMsg  IntPtr hWnd  int wMsgFilterMin  int wMsgFilterMax  int wRemoveMsg     DebuggerHidden  DebuggerStepperBoundary  DebuggerNonUserCode  DllImport  user32 dll   EntryPoint    GetMessage    public static extern int GetMessage out NativeMessage lpMsg  IntPtr hWnd  int wMsgFilterMin  int wMsgFilterMax     DebuggerHidden  DebuggerStepperBoundary  DebuggerNonUserCode  DllImport  user32 dll   EntryPoint    TranslateMessage    public static extern int TranslateMessage ref NativeMessage lpMsg     DebuggerHidden  DebuggerStepperBoundary  DebuggerNonUserCode  DllImport  user32 dll   EntryPoint    DispatchMessage    public static extern int DispatchMessage ref NativeMessage lpMsg     DebuggerHidden  DebuggerStepperBoundary  DebuggerNonUserCode  public static bool ProcessMessageOnce         NativeMessage message   new NativeMessage         if   IsMessagePending out message           return true       if  GetMessage out message  IntPtr Zero  0  0     -1          return true       Message frameworkMessage   new Message                 HWnd   message handle          LParam   message lParam          WParam   message wParam          Msg    int message msg             if  Application FilterMessage ref frameworkMessage           return true       TranslateMessage ref message       DispatchMessage ref message        return false      Then  you can loop safely by doing something like this   while  true      ProcessMessageOnce

User · Answer

Another way is to use Debugger Break   before returning from Main method

[c#] Why is the console window closing immediately once displayed my output?

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