void swap(int *x, int *y) {
	if(x == y)
		return;
	*x ^= *y;
	*y ^= *x;
	*x ^= *y;
}
void cocktailsort(int *a, size_t n) {
	while(1) {
		
		char flag;
		size_t start[2] = {1, n - 1},
			   end[2] = {n, 0},
			   inc[2] = {1, -1};
		for(int it = 0; it < 2; ++it) {
			flag = 1;
			for(int i = start[it]; i != end[it]; i += inc[it])
				if(a[i - 1] > a[i]) {
					swap(a + i - 1, a + i);
					flag = 0;
				}
			if(flag)
				return;
		}
	}
}

int main(void) {
	int a[] = { 5, -1, 101, -4, 0, 1, 8, 6, 2, 3 };
	size_t n = sizeof(a)/sizeof(a[0]);

	cocktailsort(a, n);
	for (size_t i = 0; i < n; ++i)
		printf(, a[i]);
	return 0;
}