8 replies to this topic

[Apprentice123]

I want to calculate the runtime, but the result is always 0

int main()

{

    time_t inicio;

    time_t fim;

    int v[5] = {3,4,3,5,4};

    int i;

    inicio = time(NULL);

    for(i=0;i<5;i++)

                 printf("%d \n",v[i]);

    fim = time(NULL);

    printf("Tempo = %f \n",difftime(fim, inicio));

    system("PAUSE");	

    return 0;

}

[WingedPanther]

The runtime for that is likely to be measured in thousandths of a second, if that.

[Apprentice123]

WingedPanther said:

The runtime for that is likely to be measured in thousandths of a second, if that.

int main()

{

    time_t inicio;

    time_t fim;

    int v[5] = {3,4,3,5,4};

    int i;

    inicio = time(NULL);

    for(i=0;i<5;i++)

                 printf("%d \n",v[i]);

    fim = time(NULL);

   [B] printf("Tempo = %f \n",(difftime(fim, inicio))/1000);[/B]

    system("PAUSE");	

    return 0;

}

But the result is 0

[Apprentice123]

Even if I convert to thousandths of seconds, seconds or hours the result is 0

[WingedPanther]

My guess: difftim(fim, inicio) is less than 1000, so dividing by 1000 results in 0.

[Apprentice123]

WingedPanther said:

My guess: difftim(fim, inicio) is less than 1000, so dividing by 1000 results in 0.

If I do not divide is also 0

[WingedPanther]

time_t has a limited resolution. Your program may be running too fast for it to measure.

[Apprentice123]

WingedPanther said:

time_t has a limited resolution. Your program may be running too fast for it to measure.

How can I increase the limit?

[WingedPanther]

The exact definition is implementation defined. That can include limits on the OS.

You can also try using clock_t, clock(), and CLOCKS_PER_SEC.