FreeBSD/dummy/max.c

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

static int pile[256];
static int pileQ[256];
static int pileR[256];

#define ARRAY_SIZE(x) (sizeof(x)/sizeof(x[0]))

__attribute__((pure)) static int compare(const void * restrict p1, const void * restrict p2) 
{
	int left	= *(const int *)p1;
	int right	= *(const int *)p2;

	return (left > right) ? 1 : (left == right) ? 0 : -1;
}

static int is_equal(const int * restrict p1, const int * restrict p2, size_t n)
{
	while (n--) {
		if (*p1 != *p2)
			return -1;

		++p1;
		++p2;
	}

	return 0;
}

static int get_max(const int *p1, size_t n)
{
	int max = *p1;

	--n;
	++p1;
	while (n--) {
		if (max < *p1)
			max = *p1;
		++p1;
	}

	return max;
}

int main()
{
	arc4random_buf(pile, sizeof(pile));
	clock_t tq0, tq1;

	memcpy(pileQ, pile, sizeof pileQ);
	memcpy(pileR, pile, sizeof pileR);
	qsort(&pileQ, ARRAY_SIZE(pileQ), sizeof(*pileQ), compare);
	heapsort(&pileR, ARRAY_SIZE(pileR), sizeof(*pileR), compare); 

	fputs("000: ", stdout);
	for (size_t k =	0; k < ARRAY_SIZE(pileQ); ) {
		printf("%16d ", pileQ[k]);
		++k;
		if (!(k % 8)) {
			puts("");
			printf("%03zu: ", k);
		}
	}
	puts("");


	printf("sort: %s.\n", is_equal(pileR, pileQ, ARRAY_SIZE(pile)) ? "KO" : "OK");
	printf("Max : %d.\n", get_max(pile, ARRAY_SIZE(pile)));
	return 0;
}