macro vs function

#include <stdio.h>
#include <time.h>
#include <math.h>
#define LOOP_LIMIT 10000
#define MAX( a, b ) ((a) > (b) ? (a) : (b))
int main(void) {
  int i, j;
  double x, y;
  clock_t stime, etime;
  stime = clock();
  for (i = 0; i < LOOP_LIMIT; i++) {
    for (j = 0; j < LOOP_LIMIT; j++) {
      x = i * 1.0;
      y = j * 2.0;
      x = MAX(x, y);
    }
  }
  etime = clock();
  printf("MACRO Version : time = %g\n",
    (double) (etime - stime) / CLOCKS_PER_SEC);

  stime = clock();
  for (i = 0; i < LOOP_LIMIT; i++) {
    for (j = 0; j < LOOP_LIMIT; j++) {
      x = i * 1.0;
      y = j * 2.0;
      x = fmax(x, y);
    }
  }
  etime = clock();
  printf("FUNCTION Version : time = %g\n",
    (double) (etime - stime) / CLOCKS_PER_SEC);
  return 0;
}