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how can i make the program depend on time

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Join Date: May 2004

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dooda man

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how can i make the program depend on time

Jun 1st, 2004

hi , i am using simple console application and i am asking about the way to make the program depend on time insead of dependng on pressing keys for example, i want siplay the word "Hello.." and after 5 seconds it changes to "World" , to elaborate .. i want system("pause") but depending on time not on keys.
thnx

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Join Date: Apr 2004

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Dave Sinkula Dave Sinkula is offline

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long time no c

Re: how can i make the program depend on time

Jun 1st, 2004

Something like this?

 Help with Code Tags 
 C Syntax (Toggle Plain Text) 
#include <stdio.h>
#include <time.h>
 
int main(void)
{
   time_t now, then = time(&now) + 5;
   if ( now != (time_t)(-1) )
   {
	  const char *text[] = {"Hello","World"};
	  size_t i = 0;
	  for ( ;; )
	  {
		 printf("\r%s", text[i]);
		 fflush(stdout);
		 if ( ++i >= sizeof text / sizeof *text )
		 {
			i = 0;
		 }
		 while ( then > time(&now) );
		 then = now + 5;
	  }
   }
   return 0;
}
#include <stdio.h>
#include <time.h>

int main(void)
{
   time_t now, then = time(&now) + 5;
   if ( now != (time_t)(-1) )
   {
	  const char *text[] = {"Hello","World"};
	  size_t i = 0;
	  for ( ;; )
	  {
		 printf("\r%s", text[i]);
		 fflush(stdout);
		 if ( ++i >= sizeof text / sizeof *text )
		 {
			i = 0;
		 }
		 while ( then > time(&now) );
		 then = now + 5;
	  }
   }
   return 0;
}

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Join Date: Mar 2004

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kc0arf

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Re: how can i make the program depend on time

Jun 4th, 2004

Hello,

Unfortunately, that code above is unfriendly to other processes on the computer, because of the infinite loop that is run. Granted, in this close example, you are looking at 5 seconds, and that won't cause something to croke.

But, if I had to do a delay in the minutes range, that would peg the CPU, and cause a system admin to come and shut you down. That might not matter today, but back in the day when CPU seconds = money on the mainframe, a loop like that could run you out of money.

There has to be a better way without doing the raw iteration!

(I had a program that needed the delay, and I ended up using a part C++ program and part of a BASH shell script so that I could do the wait() command that did not use CPU power during the delay)

Christian

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Join Date: May 2004

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FireNet

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Re: how can i make the program depend on time

Jun 5th, 2004

You could use GetTickCount().

 Help with Code Tags 
 C Syntax (Toggle Plain Text) 
double next_time  = GetTickCount();
 
while (true)
{
       if(GetTickCount() >=next_time + 100)
       {
             cout<<"Bong\n";
             next_time  = GetTickCount();
       }
}
double next_time  = GetTickCount();

while (true)
{
       if(GetTickCount() >=next_time + 100)
       {
             cout<<"Bong\n";
             next_time  = GetTickCount();
       }
}