Execute something after a certain waiting time specified in the code in C++?

Question

I'm trying to make a basic snake game in C++, I made a basic grid with a orl[x] and ory[y] arrays, and now I'm trying to add the snake.

Basically I want the snake to move until a certain key is pressed and move one array at a time. I tried using something else than timers but it is executed instantly. I need a timer so that the snake keeps doing that every second until a key is pressed. If you ever played snake you know exactly what I mean.

I need to make a timer in C++, but I don't want to implement an ENORMOUS code by creating a timer and not understand anything from my own code. I want it as simple as possible.

Any idea how I could do this? I looked into the time header library but found nothing useful in there.

What operating system are you using? Related question: how are you drawing the snake on the screen? — Robᵩ, Feb 24 '12 at 18:28
you can easily use [ctime](http://www.cplusplus.com/reference/clibrary/ctime/difftime/) to many a dead simple timer class. — David, Feb 24 '12 at 18:30
you don't *make* a timer.. for a pure c/c++ standpoint it's not even possible. you have to use some system API/syscall/... — Karoly Horvath, Feb 24 '12 at 18:30
I'm using windows and @yi_H, please explain more of that. If a timer is impossible please show me an alternative to a moving snake — Bugster, Feb 24 '12 at 18:31
@Dave: you have to check the time constantly. active wait is a bad idea. — Karoly Horvath, Feb 24 '12 at 18:31
@ThePlan: what I wanted to say is that you have to use some system call.. of course you can wrap that in a c++ timer class if you like — Karoly Horvath, Feb 24 '12 at 18:33
@yi_H it's perfectly fine for his project. Besides - in the game world is entirely normal to consume all cpu resources without a second thought. — David, Feb 24 '12 at 18:34
@ThePlan yi_H is complicating your life for no reason a beginner needs to worry about. Do what I said. :) — David, Feb 24 '12 at 18:36
Dave tries to force on you a bad practice. just wait a bit and check the upvotes... — Karoly Horvath, Feb 24 '12 at 18:37
heh - ya true. just check the upvotes. it'll probably just say to sleep — David, Feb 24 '12 at 18:38
I think I'll find an alternate sollution to this, since timers seem so complicated if not impossible. — Bugster, Feb 24 '12 at 18:39

score 1 · Answer 1 · answered Jun 27 '14 at 19:56

I'm adding this answer since no C++11 answer currently exists.

You can do platform-independant waiting using std::this_thread::sleep_for

void millisecond_wait( unsigned ms )
{
    std::chrono::milliseconds dura( ms );
    std::this_thread::sleep_for( dura );
}

score 1 · Accepted Answer · answered Feb 24 '12 at 18:30

1

The sad truth is that Standard C++ doesn't really have support for this type of behavior. Both Windows and Posix support a sleep function which would allow you to do this. For a higher level solution you may look at Boost::Threads.

answered Feb 24 '12 at 18:30

Joel

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there is also `usleep` and `select`. – Karoly Horvath Feb 24 '12 at 18:33
Most professionals don't have access to C++11 yet, but if you do, then by all means. – Joel Feb 24 '12 at 18:46

score 1 · Answer 3 · answered Feb 24 '12 at 18:34

If your on linux, you can use "time.h"
Here is a quick function to wait a number of seconds.
You could modify it for milliseconds if you'd like.
Also, are you using the ncurses library?

#include <iostream>
#include <cstdlib>
#include <time.h>

void SleepForNumberOfSeconds(const int & numberofSeconds);

int main(){

    std::cout << "waiting a second.." << std::endl;
    SleepForNumberOfSeconds(1);
    std::cout << "BOOM!" << std::endl;

    std::cout << "waiting 5 seconds.." << std::endl;
    SleepForNumberOfSeconds(5);
    std::cout << "AH YEAH!" << std::endl;

    return EXIT_SUCCESS;
}

void SleepForNumberOfSeconds(const int & numberofSeconds){

    timespec delay = {numberofSeconds,0}; //500,000 = 1/2 milliseconds
    timespec delayrem;

    nanosleep(&delay, &delayrem);

    return;
}

http://stackoverflow.com/questions/7827062/is-there-a-windows-equivalent-of-nanosleep — Karoly Horvath, Feb 24 '12 at 18:38

score 0 · Answer 4 · answered Feb 24 '12 at 19:39

0

If you're using windows, check out the SetWaitableTimer windows api call. I can't supply an example as I'm on an iPad at the minute, but it does what you need.

Good luck!

answered Feb 24 '12 at 19:39

Execute something after a certain waiting time specified in the code in C++?

4 Answers4