Member Avatar for delle

I wrote a little test program to try to figure out some problems I am having in another program I'm working on.

Code:

# include <iostream>
# include <string>
using namespace std;

void ahoy(string nameEntered)
{
	cout << "Ahoy, " << nameEntered << "!" << endl;
}

int main()
{
	string name;
	cout << "enter your name: ";
	getline(cin, name);
	ahoy(name);	
	return 0;
}

I am using Visual C++ 6.
Problem 1: After I enter keyboard input I have to press enter twice. Why not once? I see this both when I am testing the program in the editor, and also when I run the .exe.
Problem 2: In the .exe, the window closes so I never see the output from the function. How can I make it pause?
I haven't dealt with C++ in a couple of years so I may have just forgotten some simple things.

Edited by Nick Evan because: Added code-tags
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Short answer: nothing in your snippet requires pressing Enter twice — typical causes are leftover input in the stream, the console/prompt not being flushed before input, or the way the program is launched (IDE/debugger vs an already-open command prompt). The code shown (getline + a print function) is fine; the behavior you see is usually an environment or buffering issue rather than a bug in getline itself.

Diagnose and fix (in this order):

  • Run the compiled program from an existing command prompt (open cmd, cd to the EXE folder, run it). If the program behaves normally there, the IDE launch/debug settings are the culprit.
  • If you ever mix formatted extraction (operator>>) with line-based reads, a leftover newline will make the next line-read return immediately. Remove that leftover newline before your getline by discarding characters up to the next newline (use the stream's ignore facility).
  • Make sure the prompt is actually flushed to the console before reading input; older toolchains sometimes do not flush automatically. Explicitly flush the output after printing the prompt so the user sees it before typing.

About the window closing: the most robust approaches are (a) run the EXE from a command shell you opened yourself, or (b) add a final, standard C++ input read that waits for the user to press Enter before exit (this is portable and preferable to invoking an OS command). As others have noted, the behavior can differ between VC6 and modern compilers; upgrading will reduce obscure platform quirks, but the fixes above will work regardless.

Quick checklist: run from cmd, ensure prompt is flushed, clear any leftover newline before getline, and add a short final read to pause the program when you need to see output. This will make the behavior deterministic across IDEs and OS versions.

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Member Avatar for XMasterrrr

first don't use the Visual c++ 6.0 it's bad and non comfartable

use visual studio 2010 and i tried your code in it and it works perfectly.

First problem : it won't happen in visual studio 2010.

Second problem : the windows closes because you are makeing the normal debug and

that's never work because you didn't give it the line to make it pause,

there are 2 ways to fix this and i suggest the second one.

the first : using system("pause"); .
the second : some thing called start without debuging and it's which all using
it's made to make you must (press any key to close the console windows) and it's
shortcut is : CTRL + F5...

this is all

Member Avatar for XMasterrrr

aha and using the system("pause");

must be before the line of return 0; excatly

Member Avatar for manojwali

Well delle, I feel that XMasterrrr is right in suggesting you to use Vs2010.
Actually, vs 6 is very good for designing stand-alone application for windows using VB 6. I also used it a lot.
There seem to be some problem with all the old C++ compilers such as vC 6++, TC or Borand compilers.
They seem to handle stream operations and input/Output operation in an inconsistent behaviour at
run-time may be due to improper algorithm used in there API design or God known what.
I myself had upgraded to vs2010 and I am working on it for quite sometime now. I am very happy that inconsistent behavior in I/O and stream operation in this period. It is very frustrating to see a program fall no mistake on our part. If VS2010's cost is issue for you, you can always look for vs express editions.

Regarding your second query, you can use system ( "pause" ), just before return statement in your program.
you will get the output to pause, when running exe file.
Thanks
-Manoj

These are my personal views and if any anybody have any differences with it. Don't brother me with cross-reference
back posts. They can use their ideas.

Member Avatar for LordNemrod

in the end of main, write
cin.get() which will wait for you to press enter so it won't close

Member Avatar for vidit_X

Don't use System("pause"), instead as LordNemrod suggested use cin.get().

Edited by vidit_X because: n/a
Member Avatar for Duki

>>Don't use System("pause"), instead as LordNemrod suggested use cin.get().

Yes, never use System("pause").

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