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Things to Avoid in C/C++ -- system("pause"), Part 4
by: WaltP - Sep 20, 2005
system("pause")I've never understood why system("PAUSE") is so popular. Sure it will pause a program before it exits. This pause is very useful when your IDE won't wait as you test a program and as soon as the program finished the window closes taking all your data with it.
But using system("PAUSE") is like burning your furniture for heat when you have a perfectly good thermostat on the wall.
Many people, instructors included, for some inexplicable reason think that making a call to the operating system and running a system command to temporarily halt a program is a good thing. Where they get this idea is beyond me. Reasons:
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It's not portable. This works only on systems that have the PAUSE command at the system level, like DOS or Windows. But not Linux and most others...
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It's a very expensive and resource heavy function call. It's like using a bulldozer to open your front door. It works, but the key is cleaner, easier, cheaper. What system() does is:
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suspend your program
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call the operating system
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open an operating system shell (relaunches the O/S in a sub-process)
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the O/S must now find the PAUSE command
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allocate the memory to execute the command
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execute the command and wait for a keystroke
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deallocate the memory
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exit the OS
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resume your program
There are much cleaner ways included in the language itself that make all this unnessesary.
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You must include a header you probably don't need: stdlib.h or cstdlib
It's a bad habit you'll have to break eventually anyway.
Instead, use the functions that are defined natively in C/C++ already. So what is it you're trying to do? Wait for a key to be pressed? Fine -- that's called input. So in C, use getchar() instead. In C++, how about cin.get()? All you have to do is press RETURN and your program continues.
posted on 2009-06-19 17:42
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