#include <stdio.h>
#include <time.h>

double getCPU(void)
{
  return (double) clock()/CLOCKS_PER_SEC; /* convert to seconds */
}

void MyExpensiveFunction(void)
{
  double g;
  int i;
  for (i=0; i<10000000; i++) g *= 2;
}

int main(void)
{
  double t0,dt;
  t0 = getCPU();         /* get initial value */
  MyExpensiveFunction();
  dt = getCPU() - t0;    /* difference to get execution time */
  (void) printf("Execution time: %g sec\n",dt);
  return 0;
}