Matlab like "tic & toc" in C

tic_toc.c

#include <time.h>

static clock_t tictoc_start = 0;

void tic(void) {
  s = clock();
}

void toc(void) {
  clock_t e = clock();

  fprintf(stderr, "経過時間は%f秒です。¥n", (double)(s-e)/CLOCKS_PER_SEC);
}