First and foremost, allow me to assure you that this post is not meant to discuss the sleep() command, mutexes or semaphores, or using threads. It is meant to address one of the most commonly asked questions by newcomers to C++, especially those who use an IDE for programming.
When my program runs, the execution window closes immediately. What is wrong? How do I hold it open/pause it?
Nothing is wrong - that is exactly what your program has been designed to do - execute, then exit.
When newcomers ask the question above, they are almost always told to use one of the following commands:
CODE
getch();
//or
system("pause");
Both of the commands above are platform specific solutions, and do not conform to ANSI standards. They use components that are found on certain architectures, but not others. It is preferable to use a solution that does conform to standards, and uses accepted C++ methods.
One such method that is also often recommended is using:
CODE
cin.get();
This solution will indeed pause for user input - as long as no characters are currently in the stream. As most applications will have asked for input several times, it is likely that there will be at least one character in the stream (often a newline) that will be captured by the
cin.get() method, and the application will continue on past.
There are many ways to do it and remain standards compliant. I will not reinvent the wheel, but will simply post one example already submitted by a member of this site - Xing (hope you don't mind me posting this).
This simple snippet is as follows:
CODE
#include <iostream>
#include <limits>
int main() {
// Rest of the code
//Clean the stream and ask for input
std::cin.ignore ( std::numeric_limits<std::streamsize>::max(), '\n' );
std::cin.get();
return 0;
}
The original submission can be found here:
http://www.dreamincode.net/code/snippet582.htmThis method is standards compliant, and will hold the command window open without invoking any executables that may or may not be present.
Of course, you can always run the program from the command line.
18 Jul, 2007 - 06:02 PM
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