Measure the cost of bounds checking

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

#define SIZE 1000 * 1000 * 400

double timing(clock_t start, clock_t finish) {
  return ((double) finish - start) / CLOCKS_PER_SEC;
}


int main() {
  int *a = calloc(SIZE, sizeof(int));
  /* walk over everything once to normalize for cache effects */
  for (int i = 0; i < SIZE; i++) { int z = a[i]; }

  /* The unchecked version */
  clock_t start_unchecked = clock();
  for (int i = 0; i < SIZE; i++) {
      int z = a[i];
  }
  clock_t finish_unchecked = clock();

  /* walk over everything once to normalize for cache effects */
  for (int i = 0; i < SIZE; i++) { int z = a[i]; }

  /* The unchecked version */
  clock_t start_checked = clock();
  for (int i = 0; i < SIZE; i++) {
    if (i < SIZE) {
      int z = a[i];
    }
  }
  clock_t finish_checked = clock();

  printf("Checked: %f, Unchecked: %f",
         timing(start_unchecked, finish_unchecked),
         timing(start_checked, finish_checked));
  return 0;
}