conio.h in visual studio

[ECE07]

Hi, I wrote a simple program in Visual Studio 2012 to add 2 and 3. The program will not run without "conio.h" and _getch();, the exe window disppears as soon as the program is compiled. Can someone explain to me why?

 #include <iostream>
#include <cmath>
#include "conio.h"

using namespace std;

int main ()

{
	int x = 1;
	int y = 2;
	int z = x + y;

	cout << z;

	_getch();

return 0;

}

[vlad from moscow]

First of all try the following code

#include <iostream>

using namespace std;

int main ()
{
	int x = 1;
	int y = 2;
	int z = x + y;

	cout << z;


	return 0;
}

and run it by pressing Ctrl + F5.

As for your question then the windows application that is MS IDE runs your code creating a console. As soon as your code finished executiong the IDE closes the console.

[ECE07]

Thank you. Yes the console disappears after running, however with conio.h and _getch it remains up. What do these functions do?

[vlad from moscow]

Function _getch checks keyboard buffer and if the user will pressed a key the function returns the control to the main and executing of the program will finished.
Header conio.h contains declaration of that function.

[JockX]

Before you get a ton of usefull replies, know just this - conio.h is not part of C++ as such, and in modern IDE, such as visual studio 2012 it is simply deprecated, and all examples of its use are getting a bit outdated.

[ECE07]

Thanks, so if I want the console to remain up I will add conio in my code. Lastly, is there a place visual studio stores the value of "z", which is 3, that I can see it without using the console. Like in MATLAB where you can type in the variable in the command line and see the result after the program ran.

[andywestken]

Thanks, so if I want the console to remain up I will add conio in my code.

There are other ways to achieve the same aim. See this old thread for further info:

Console Closing Down
http://www.cplusplus.com/forum/beginner/1988/

Andy

[Duthomhas]

Better yet

Keep the console open long enough to see your program's output
http://www.cplusplus.com/articles/iw6AC542/