C Tutorial/time.h/difftime
difftime
Item Value Header file time.h Declaration double difftime(time_t time2, time_t time1); Return returns the difference, in seconds, between time1 and time2( time2 - time1).
<source lang="cpp">#include <time.h>
#include <stdio.h> int main(void) { time_t start, end; volatile long unsigned t; start = time(NULL); for(t=0; t<500; t++) ; end = time(NULL); printf("Loop used %f seconds.\n", difftime(end, start)); return 0; }</source>