// To compute elapsed time (as if you used a stopwatch)
// instead of the sum of the time that each thread used, 
// put this at the top of your file:

#include <time.h>
#include <sys/time.h>

// Declare these variables:

double myelapsed ;  // used for timing
struct timeval myt0, myt1;

// To begin timing:

   gettimeofday (&myt0 , NULL );

< put code to time here >

// To end timing:

   gettimeofday (&myt1 , NULL );

// To comput the elapsed time:

   myelapsed = (double)( myt1.tv_sec -myt0.tv_sec );
   myelapsed += (double)( myt1.tv_usec -myt0.tv_usec )/1.e6;

// Print the result. 

   printf("Time = %f.\n", myelapsed);