Thread: Closing the input stream after a certain time

  1. #1
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    Oct 2005

    Closing the input stream after a certain time

    Hello, I am a fairly experienced C programmer and now I am trying my hand at C++.
    Is there any way to close the input stream in a program after a certain amount of time has passed? Also, is there any way to indicate that the time is passing?
    Thank you very much.

  2. #2
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    Jan 2005
    AFAIK there are only non-standard ways of doing this that depend on your OS and compiler. Normally cin waits for the user to enter their input before returning control to the program. A function like kbhit() might be available on your platform that returns true only if the user hit a button. You can use Sleep or sleep in a loop to check periodically and after a certain amount of time stop checking.

  3. #3
    and the hat of int overfl Salem's Avatar
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    Aug 2001
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    Probably the same way you would do it in C, and that would depend on which OS and Compiler you have.
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  4. #4
    Registered User major_small's Avatar
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    May 2003
    well, there's a kinda semi-standard way of getting around what you want... you can't really close the input stream, but you can use your own input stream and cut it off, and AFAIK, the only way to time something and accept input at the same time is system-dependant (like others have said)
    #include <iostream>	//for I/O
    #include <ctime>	//for standard time functions
    void timeAndSpin(const int seconds);	//a timer with a spinner
    int main()
    	char*line=new char[20];		//to hold the input
    	std::istream*input=&std::cin;	//assign the standard input to your
    	std::cout<<"Enter your name: ";	//ask for input	
    	input->get(line,20,'\n');	//get it with your stream
    	std::cout<<"You Entered: "<<line<<std::endl;	//confirmation
    	input=0;	//"close" your stream
    	delete[]line;	//free up the memory
    	timeAndSpin(5);	//run the timing function
    	return 0;
    void timeAndSpin(const int seconds)	
    	char*spinner="|/-\\";	//use a spinner to time
    	int i=0;		//for the position in the spinner
    	int time=seconds*CLOCKS_PER_SEC;	//use a standard constant
    	int start=clock();	//start the timer
    	int end;		//save memory for the end of the timer
    	//here we create an interval - how often the spinner moves.  I set it
    	//to every 10th of a second
    	const int INTERVAL=static_cast<int>(CLOCKS_PER_SEC*0.1f);
    	//start the spinner
    		//set 'end' variable to now
    		//if it's time to update the spinner
    			//update the 'i' variable
    			//output some backspaces, the spinner, and the time
    			//NOTE: I/O functions take ALOT of time and processing
    			//power - try not to keep this in a tight loop
    				<<spinner[i]<<' '<<end<<std::flush;
    	}while(end-start<=time);	//keep doing it until time runs out
    of course putting the timing and input together right is up to you, and that method is pretty processor-intensive (using clock() with a loop)... basically you'll need to find a way to time something and accept input at the same time, and a way to, when you get the input or time runs out, break out of that routine.
    Last edited by major_small; 10-08-2005 at 12:28 AM.
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